A very handy tip if you are OOP and betting into a guy who you think is on draw and has missed by the river, just check - often they will think they 'have to bet' to stand a chance of winning the hand and bet 1/2-full pot to you - much free money..
Technically known as 'inducing a bluff' and it's bread and butter at $100 NL + but not often seen at micros.