I genuinely tried to get better at this game.  I played about 50 one-on-one matches.  After each loss I would think "What could I have done differently?"  There were a few victories after a while, but generally I still get beat easily when I play.  Then I quit. 
 
A lot of times I would fail to defend against a rush, or I would rush and fail, or the opponent would just grow a lot faster than I did. 
 
I have a few theories:

1.        I’m always British.

2.        This is the first RTS I’ve played online, so I need more experience.

3.        I usually get matched against better players.

4.        I haven’t earned enough good deck cards yet.    

"

I genuinely tried to get better at this game.  I played about 50 one-on-one matches.  After each loss I would think "What could I have done differently?"  There were a few victories after a while, but generally I still get beat easily when I play.  Then I quit. 
 
A lot of times I would fail to defend against a rush, or I would rush and fail, or the opponent would just grow a lot faster than I did. 
 
I have a few theories:

1.        I’m always British.

2.        This is the first RTS I’ve played online, so I need more experience.

3.        I usually get matched against better players.

4.        I haven’t earned enough good deck cards yet.    

"

This game is old.

Don't turtle. Don't rush. Assume your guy is going to harvest, upgrade some shit, and make like 30 units before moving in. So what you do is make 10-15 or so units as quickly as possible and move in, then set a waypoint for your barracks and set the spawn to infinity. THEN start harvesting, if they didn't make any significant military building before you show up your group is now keeping them from being able to. Old fashioned RTSs begin and end in like the first 10 minutes. A lot of people who keep getting beat are compelled to set up a little fortress before doing anything and that is a recipe for failure. Unless you're in a game with like 5 other sides.

Read this, maybe it will help.
 
 http://www.crispygamer.com/columns/2008-09-09/rush-boom-turtle-you-suck-at-rts.aspx