Before I get into specific tells, there are a few guidelines that apply whenever you see a tell and you're trying to analyze it:
1. At the lower limit games, where most of the players aren't too sophisticated, popular belief holds that the best way to fool other players is to act weak when you're strong and act strong when you're weak. It's very common to see players who have a full house act like they can't beat ace-high and players who can't even beat ace-high act like they have a full house.
For this reason, I'll advise you, if you're going to act at all, to act like your hand is strong when it is strong and to act like it's weak when it is weak. Many of your opponents will think you are lying, because that's what they would do, and they'll often misread your hand.
2. If you're trying to work out what a possible tell means, don't make things harder than they have to be.
If you think the other player doesn't know that he just gave you a tell, you can go with what it usually means. If you think he is acting and he gave you that tell knowingly,. you can proceed from there accordingly.
3. If you spot a tell and you honestly cannot decide what it means you have several options. You can stop the action, think about it until you arrive at a conclusion, and then make your play. Alternatively, you can ignore it completely and rely on the other information you have to help you evaluate the hand.
Chances are if you can't decide what a tell means after reading this, it's probably not that valuable to you. The best you can do is remember the tell, remember the cards the player had when you spotted his tell, make a note of it, and think about it after the game.
4. A player's general demeanor during the play of a hand is a big clue as to the strength of his hand. If he appears to be happy, enthusiastic, and not worried, he probably has a good hand. If he appears to be un-happy, acts disgusted with his hand, or makes negative remarks, he probably has a bad hand. His general demeanor won't tell you exactly what his hand is, but it's certainly one more bit of information that you can consider when making your decisions.