Hi Midnite,
First, I assume you are talking about online 6-max cash games correct? As with any poker question like this, there is not a concrete answer or exact formula to follow. You must be flexible and creative to succeed. However,there will be a few key factors that should help you determine your postflop decisions:
1) Your Opponent's style- As a general rule, tend to fold more against tighter opponent's showing strength postflop, but tend to bet more if they seem weak. Against looser opponents tend to bluff less, but value bet more liberally with medium strength made hands. (having a HUD display will make catergorizing your opponents much easier)
2) Stack sizes- As a general rule, play tighter postflop (and preflop) with shorter stacks since you are more likely to go to showdown. With deeper stacks, you can loosen up and bluff/semibluff postflop more often against the tighter opponents. Bluffs are usually more effective with bigger stacks left behind. "The fear of the future big bet" usually helps your fold equity.
3) Position- As general rule, continue postflop more often when in last position, and fold more often out of position.
4) Your current table image- As a general rule, with a tighter image, bet/bluff more often postflop. With a looser table image, bluff less and value bet more often.
5) Hand Ranges- this is a crucial skill to learn when deciding whether to proceed in a hand postflop. You must be able to put all of the above information together, and accurately put your opponent on a hand range, while disguising your own range.
These sound simple, but they will help you greatly in deciding how to continue postflop.