SiX, (in before Turble, Gadarene, DragonAsh, and Senor Beef answer all of your questions.)
“Loose” generally refers to how many hands a player decides to play. A loose player is playing a lot of them, widening their range for each position (assuming they’re even cognizant of position.) Contrast with a “tight” player. “Aggressive” and “passive” are defining how often the player raises versus calls. So, one can be tight aggressive: playing only a few hands, maybe only 10-15% per ‘orbit’ (each time the button goes around, so every 9 or 10 hands in a full ring)—tight—but playing them by raising or folding, not calling. (Aggressive) Or loose passive, playing a lot of hands (30% of the hands they receive or more), but only checking and calling most of the time.
Chiming in along with RickJay, at low limits, the rake is usually the most successful player there, measured in big blinds per hour won. At extreme cases (a 10% uncapped sounds like this, unlike capping it at 5 or 6 bucks, though I’ve read of some crazier set-ups.) it’s extremely hard to make a profit playing these games, absent casino promotions or other ways of returning some of the rake to you. Again, for some rake structures, the rake is the only player at the table making money. Chew on that for awhile.
So, what should you do? First, determine what your goal is: to have fun (perfectly fine), to make money (difficult to do at low limits due to rake), scratch your ego. If you want to make money, and you want to play low limits, one strategy bandied about places like twoplustwo.com (their low level NLHE forum is fantastic, as are their low level tournament forums) is to play tight, wait for a good hand, and value bet it relentlessly. If they won’t fold, why not keep betting? There are many online resources about starting hand charts. I like the one from David Sklansky and Mason Malmuth’s Hold 'Em Poker for Advanced Players, but YMMV. It’s centered around the limit game, and is quite old, but Sklansky and Malmuth are just fun to read. The Theory of Poker is a seminal text from Sklansky, one I often revisit.
Some knowledge of tournament play would be helpful too. You probably won’t need to know anything about Nash equilibria in the NLHE context—people won’t shove light enough—but knowledge of what to do near the bubble, and generally, tournament ideas such as steals and re-steals would be helpful to know. I like Harrington on Hold’Em as a basic primer, though the game has gotten much more aggressive since he wrote those three books.
As to tells, if you are really worried, Mike Caro’s book of tells is maybe $20-30 bucks, and should ‘tell’ you everything you need to know on the subject. I wouldn’t worry about it, other than reminding yourself to take your time before every decision, and ideally, have a plan for what you’d like to do. Anyway, the very basic gist of Caro’s book is that everyone is trying to lie to you. If they act confidently—staring at you, talking loudly, etc…, they’re weak; if they act sheepishly—looking away from you, seemingly uninterested in the hand—they’re strong.
Kicking it old school, the gambling authority John Scarne said about poker that it was a game that had to be played for money, and ideally the stakes had to hurt a bit for the game to be fun. Not a lot, and not for stakes that would put your entire bankroll at risk, but enough that the players cared a bit about each decision. The flip side of that is very successful players are envied for their ability to seemingly not care about the money at stake. So it goes.
