So how do you find the sheep?
The size of the blinds is certainly your first guide. Smaller blinds attract weaker players. Still, if the bets are smaller, potential winnings are smaller as well. The trick is to find the biggest game where you are significantly more skilled than the average at the table.
If you play in the same place often, you already have an advantage. Keep a notebook to track the players you play against. Really, I'm serious. This is one of the better investments you can make. Write down which players are calling stations, which play deceptively (check-raising, bluffing), which play aggressively, etc. Note who can be bluffed off of a pot and who will call to the river even with average cards. When you see a table with several non-deceptive calling stations it's time to sit down.
Some players come to the table to win, others just want to have fun. If you see a player (or better yet a group of players) who are drinking and laughing it up, that's a great sign that you found a good table. If they are playing as loose as they act, sit down and bring an extra rack to carry home their chips.
Some players just can't get enough, and will play all day and late into the night. Many of the best games can be found when the competition is beaten down from countless hours of play. If you're a night owl, consider showing up at the casino very late fresh and rested. Look for signs that players are weary and see if their play is as tired as they are.
When you find your sheep, remember to keep playing your A-Game. Don't be lulled into playing a loose game just because everyone else is. Wait for a really premium hand, and then play it hard.
A table full of sheep will certainly attract a few sharks (you're not the only one!) Unless you have great cards, it's probably wise to stay out of their way if they really go after a hand. After all, they are doing the same thing you are - waiting for a great hand and playing it hard.
PS - If you're playing at one table and see a better one, you can ask the dealer or the floor person to arrange a table change for you. They will seat you at your desired table as soon as there is an opening. If there's a board waiting for your game, the person on that wait list will get your old seat.