Tell me what hands you have in Poker?

Poker Tells that Say:

I Have a Good Hand

Acting Uninterested in a Hand While Still in It

This is usually a sign of a strong hand. The player is pretending that he's not excited about his cards while he is.
Sighing and Shrugging

If a player makes a show of sighing or shrugging and says things like "Oh, I guess I'll call" or even "Why am I calling?" he probably is overacting and is trying to hide a big hand.
Glancing at Chips after Looking at Hole Card

When a player looks down and sees strong hole or pocket cards, he may glance over at his chips to see just how much he can bet.
Shaking Hands

If you notice a player's hands are shaking as he places his bet, he probably has gotten a really good hand.
Rapid Breathing

Some players can control the shakes, but it's harder to control the heart-racing that comes when you see pocket aces or hit the flop really hard.

If you can see a player's chest visibly rising and falling, they have an excellent hand!

Staring Down Other Players

If an opponent is staring you down, he's trying to represent strength. Usually, he has a weak hand.

He might have something, but it's something that can be beaten or drawn out on.
Holding Breath

Inexperienced players will often hold their breath if they are bluffing.

Checking Their Cards After a Flop

If the flop shows the possibility of giving someone a flush or straight draw, watch for people re-checking their hole cards.

They're checking to see if they have a piece of it, whether that black Ace was a spade or a club.

The player doesn't have the flush or straight at that point, else he wouldn't have to check it.
Taking a Long Time Before Calling a Bet

If a player looks into the pot, he is probably doing some calculating in his head. He's figuring out the pot odds to see if it's worth to try and catch the cards he needs to complete his drawing hand.

A final note: more experienced players may give off false tells, so the first thing to read about other players is if they're novices or pros.