When to raise the flop with medium hands?

[DandyJam]

After reviewing my game at the $0.5/1 6-max tables I started thinking I might not be betting/raising the flop enough with my medium strength hands such as TP, focusing too much on keeping the pot size managable. This, I think, puts me in the awkward sitation that I don't charge draws enough while I often have to pay off draws that hit on the turn or river since I have underrepresented my hand and not taken command. I find that this happens both when I'm InP as well as OOP.

I have no particular hand examples at the moment but I thought maybe you guys have some good examples where you bet/raise to charge draws, or check/call to keep the pot small? Examples both InP and OOP appreciated.

Here's a made up hand of the type of situation I'm talking about:

Hero gets K[img]/images/graemlins/diamond.gif[/img]Q[img]/images/graemlins/club.gif[/img] and raises to $3.5 first in from the CO. Button folds. SB, some typical 30/12/2, calls. BB folds.

Flop ($8): K[img]/images/graemlins/heart.gif[/img]J[img]/images/graemlins/heart.gif[/img]7[img]/images/graemlins/spade.gif[/img]

SB leads for $6. Hero calls $6.

Turn ($20): 9[img]/images/graemlins/spade.gif[/img]

SB leads for $15. Hero???

Now this is a typical situation where I have no clue where I stand. Have SB bet a draw? Did it just hit? Did he have a stronger made hand on the flop already? If I call it's often just to find myself folding to a river bet. If Villain had checked I often just check behind. Then when the river brings a blank, most of the time I feel obligated to call a bet since Villain could be betting a busted draw or looking for a cheap showdown with a weaker holding. However, what's most likely to happen is that Villain has a stronger hand and I'm the one paying off.

I really thought I was on top of my flop game, but as said I feel I might have been too eager to manage pot size instead of getting value from my good hands.

All input welcome!