You need ships to cover your satellites on each continent. If there is no ship on a continent then the aliens will just shoot down your satellite. So, having interceptors in each continent is a good call.
I think some missions are just tough and you might lose people unless you're very careful. Dan lost some people but not everyone. I think he did a good job.
Just FYI, I think the outsider alien only shows up in crashed UFO missions. So you don't need to bring the arc thrower to every mission unless you're planning on capturing other types of aliens for free laser weapons.
Just FYI to all players. If you shoot using holo-targeting(upgraded heavies) then everyone else gets an aim bonus against that enemy for that turn. So your heavy should shoot first, if you have other people shooting the same target.
Never leave a soldier out of cover. Aliens have their own movement turn so they can come out of nowhere and kill you.
Always try for full cover over half cover. This is more important in harder difficulties.
You can tab through soldiers. This is helpful so you don't accidentally move a soldier when you were trying to select one.
Avoid overwatching with a shotgun. Instead overwatch with a pistol. I believe you can switch guns with X. This is good because shotguns will usually miss at long distances but pistols will have a higher chance of hitting.
Snipers are amazing.
Reload. If your soldier has nothing to do then reload.
Never dash except when you have to. Moving then going into overwatch is usually a better option.
That's all. Have fun and I'm sure you guys will pick up the rest of the basics as you go along.
izzygraze's comments