First thing, 10 bucks is not enough money to play with NL. One bad hand and poof, you are done for the night. So, don't take anything from your session with two of your friends, it could be nothing more than a string of bad luck. If you do this week after week and still continue to lose, then that becomes a pattern.
Now, I'm not very good and fairly new at this game myself, but a couple of things I've picked up. First, everyone who says know the player and not the cards is dead right. There are a lot of guys I play with who are very loose, betting big at nothing. So, I simply wait until I have something decent, then try and pick em apart. Usually they will play with me, and 9 times out of 10, they'll be sitting on cards that they have no business sitting on.
Second, I never try and chase cards, and try to get anyone who is chasing out quickly. If I have, say, pocket Qs or higher, I'll toss in 5 bucks or so pre-flop. That usually will take care of most guys holding crappy hands, 6-7, J-10, etc, who need a lot of help from the river to complete a flush or a straight. Also, it gets your loose players into the pot bigger, which makes it harder for them to simply walk when, in all likelihood, the flop gives them nothing. On the flip side, if I have, say, pocket cards suited, and get a card or two on the flop towards my flush, I am never staying in if anyone raises any decent amount of money. I've been burned too many times chasing dreams of a flush, only to have nothing come up, and then I've got nothing. It helped me every once in a while, but on the whole, I usually lost while chasing.
Also, this doesn't apply to online, but know how to goad your opponents. Way too many times I've talked guys into calling me when they had every intention of folding. This only works against very bad/insecure players, but if you've got a couple, work them. It helps with these guys if you've successfully pulled off a bluff once or twice during the game, and then let the table know about it. That always puts a little bit of a doubt in their mind, and while in all likelihood, I've got two pair or three of a kind, they don't want to give up their cash only to have me announce to the table that I'm bluffing. So my rule, bluff early, trap late.
Now, most of this probably applies to average/bad poker players, since this is who I play against, so keep that in mind. But, over the last two weeks, it's been good enough to net me close to 200 bucks profit, which I'd guess is close to 70% of the money that was in play those two weeks. Not a bad run.