I beat a player rated 2008..

Playing black .. My response to d4 was c6. Slav defense..I just Beat a player rated 2008.
a simple queen exchange turned nightmare.. Major blunder on his part it appeared to be a drawish game until his blunder at move 18..
after he resigned =)
What do you think of my play?

A link to game game would be easier to follow. Probably here:
de.lichess.org/Q4GmZU9n

"A good chess player is always lucky" a grandmaster once said.
You were completely losing inbetween although you didn't play bad - especially for your rating.

I would advise you to take a little look into opening principles as it makes it easier for you to play. Like "don't move too many pawns" and "develop knights and bishops before the rook and queen."

Also it's better to develop your pieces so, that you don't block your center pawns as they often have a big influence in the center and give a nice initiative. (Look at move 9, it's better to put your bishop one square further).

I can't see the link to the game.

Learn how to play the opening. Not a specific opening, but the general principles of it. Dolg has already mentioned some. Even in Wikipedia you'll find a great article about it.
Your play was ok for your level. Keep improving!

If you want free game analysis pm me. :) Also I offer free coaching/instruction to anyone below 1600. In the game #2 posted I see quite a few errors in the opening that can be easily fixed.

Qxe3!! winning the queen