NLHE
I love to raise blocking bets! It makes me smile. Once in while, what I believe to be blocking a bet, will actually be a set. They'll make a small bet hoping I will raise, and I do, then they flat call or 3 bet.
In an instance when you open pre-flop with a raise and get called, then the caller bets 1/2 pot size or less into you on flop. What do you guys look for to determine the difference? When there's a wet flop like 8d 9d 3c where there's possible straight and flush draws out there I'm more likely to raise. When it's a pretty dry board and low/mid cards I think they may have hit their set. Other than that, I'm going on instinct and feel for the opponent that I'm in the pot with. Online I look for speed of their pre-flop call and post flop bet. In person, I'm looking for any sort of tell.
So, what I'm trying to ask in this drawn out post is...
What do you look for to determine if a bet is a blocking bet?
How much do you slow down when there's a player behind you yet to act?
p.s.
This is assuming that I missed the flop and don't have a strong hand.