• Most importantly don’t rely on the Autosave in Mass Effect. After a big fight, save. Before a boss fight, save.
• If you only use one weapon make it the shotgun. It’s excellent at medium range, and carnage is good for hitting long range targets once you learn how to aim it well. Smack the 500% damage mod in the specter version shotgun and you have something close to a One Hit kill stick. It’ll overheat after every shot, but this game isn’t about the run ‘n gun. It's about picking your shots.
• If you only use one Biotic make it Singularity. It’s the most powerful way to turn enemies into helpless flying targets. If you only use one Tech make it Overload. Everyone has essentially two hit bars. Shields and Health. Overload cripples the shield half of their defenses.
• Gaining achievements makes it easier to play this game. Things like bonus Health, bonus XP, and weapons and skills not typically available to your class are unlocked in a second play through by this manner.
• It’s better to be Great in one type of weapon than good in all of them. Pick a weapon, even if it’s just the pistol, and keep it leveled very high. Either that or upgrade a weapon as far as you need to to unlock the one you’d rather be using and level that one up for the rest of the game.
• Fire in controlled bursts. Leaning on the trigger overheats your weapon quickly.
• Using Carnage on a Shotgun does not count toward it overheating.
• It pays in Biotics and tech, unlike in weapons, to have a good balance. You’ll be using most (if not all) of them often. Even one point in stasis can do you some good in a close fight.
• You shouldn’t be spraying gunfire randomly. Bringing up the combat wheel often in combat. Pick a dangerous target, use a smart combination of Powers on it, than fire.
• It’s a good idea to pick Charm or Intimidate and keep it leveled high. They both serve the same purpose, which is making the game easier outside of combat.
• You don’t want a screaming mad Krogan in your face. Keep them at bay with bionics and fight them ranged. You shouldn’t be doing much melee anyway, but foes much taller than you thrive on it and are very good at it. If you see one charging at you, and they will, using lift on it is a good idea. He'll rise up and go flying over your head as if he'd been hit by Throw as well.
• It’s tedious, but properly switching out upgrades in between firefights so you shooting Synthetics and Organics with Synthetics and Organics bullets can make a big difference in combat.
• Sheppard should always have the best of everything. No AI is going to play this game better than you are when you know where and when to shoot and where and when to best use powers. That’s why it’s best for you to control that aspect of the game, and not set them to use powers automatically in the options.
• It’s generally better to hit once with a very powerful attack (Like with a Shotgun) than very often with a weaker one (Like an Assault rifle).  
• The Assault Rifle shines when mowing down lots of weak enemies. The Shotgun is for tougher stuff, and the Sniper Rifle is obviously best used for long distance preemptive strikes.
• What the Mako is aiming at isn’t necessarily what the Mako will hit. If you drive on uneven terrain the shot can fly in another direction entirely.
• Geth are typically very weak to a Sabotage/ Overload combo.
• Characters each have a special leveling bar just for them. Asari Scientist, for example is Liara’s. These are all excellent upgrades. Take them all.
• Use a mix of all powers available to you in a fight. For example: A Carnage Blast from your shotgun modded for Max Damage isn’t going to do a thing if it doesn’t hit somebody in the face. If one member of the party puts them in the air, the other Overloads their shields, and you drop a Carnage on the guy… That’s gonna mess him up even in Insane Difficulty.
• For the most part you can and should keep your enemies helpless. Obviously you can do this best with Biotics using throw, lift, and singularity. Neural Shock and Stasis can do this too. As do Grenades modded with High Explosives and weapons with powerful mods that increase the force of impact. If you have a weapon with mods that increase your melee power, this too can will knock them over when you hit them with it. Always be aware of something that can explode by being shot. They put them there for you to shoot at. If somebody gets near to one of them blow it up to dish out big damage in addition to sending them flying.
• Its easiest if each member specializes in something only they can do in the party. Someone handles the combat, someone handles biotic, someone handles tech. And everyone only needs to use one type of weapon the whole game. It’s possible to Play as a Solider, take Ashley and Wrex with you everywhere, max out all your weapons stats and switch them around constantly in combat to blow holes into everything and have a great time doing it. It’d just be much harder than with a balanced party who focused more on their Powers.
• Keep in mind you only need to train up to Master Overload and Master Sabotage to open and unlock the game items.
• Micromanaging pays off big in this game. Ideally before every mission back in the Normandy you should make some lengthy preparations. First, be sure who you’ll take with you and strip everyone else down to a weaker version of weapons and armor than what they currently have. Than pull out all the mods they might be carrying. Make sure the two going with you has the best of everything equipped starting with their primary weapon, than their armor. Next upgrade that weapon and armor with your best mods, and finally put the best item in the biotic or tech slots. Than reequip the rest with the best of what remains. You don’t want to check Wrex’s inventory midgame and see he’s still got the weak sniper rifle he came into the game with. Finally, sell off the expensive gear you have left but can’t use and grind the cheap stuff into omnigel. You might want to keep a hold of a few key upgrade mods for other characters, but for the most part you’ll constantly be finding better equipment so no upgrade stays useful until you near the endgame.
• Lift and Throw can be very potent combination. An enemy that is lifted up can be thrown a great distance is in real trouble in certain areas. If one flies off a building, or down a ravine, or over a rail, or anywhere where they can’t get at you means instant death to them no matter how high their health and shields are.
• Enemies who are flying in the air, thrown to the ground, or stunned are totally helpless. Sometimes it’s better to shoot these guys while they are in this state, and sometimes it’s better to focus on the others first. It depends on the number of enemies. Lots of enemies means you need to take a lot out quickly. Get tough ones in the air than shoot down the weak. In Small groups pick the toughest foes attacking you and get them helpless so you can take them out before they have a chance to harm you.
• Warp is totally useless or utterly vital. It’s best used when an enemy’s health bar turns white. They’ll be hard to kill like that. That’s where Warp steps in and neutralizes the effect. In Insane mode you’ll need Warp in many fights because everyone is much healthier in general, but in lower difficulty games you can go start to finish never needing to use it.
• You don’t want to walk around picking up grenades and health packs after you’re got the maximum amount you can carry. Always buy the upgrades for these in shops and always know how many of you can have versus how many your currently carrying.  Generally you want to keep them near that max number so in a tricky spot you’ll have a lot of resources.
• Mako’s jump jets are there mostly so you can get around tricky spots and hop over missile fire. Dodging missile fire is very useful. And although it might be boring, waiting a few minutes in between fights so the shields can completely recharge is a good idea and a way to save on Gel Packs.
• Mako’s heavy Cannon takes a few seconds to fire. Lean on that button and always try to aim well so as soon as it can shoot, it will.
• Geth Armature tanks can be run over with the Mako making them defenseless for a few moments.
• Make sure someone has a Combat Scanner mod equipped at the highest level available. That way you will usually know your position in relation to the enemies which is important at difficult levels of play. It’s best equipped in a gun of a person who rarely uses it. Like someone who uses a pistol, and mainly fights with powers.
• Using Lift to put an enemy up into the air and throw a grenade at the spot they’ll land at is a good way to get both fall and grenade damage on them while keeping them helpless. It also lets you focus on shooting other enemies.

I had no idea about the geth armature and the shotgun things! Thanks! :)

I can not describe my appreciation for some of these pointers.  Thank you.