Something that I have learned lately from going back into my play, doing some significant reading and reviewing is that players tend to be afraid of a flush way more than they practically appear. If you think about the situation you are looking at for a tight player a flush draw actually makes up a very small percentage of hands that they may play (assuming a 10-15% opening range). For a looser player it expands slightly, but not significantly (20-35% opening range). The way I approach if I hit a flop and it is coordinated in a suited fashion I play hard, if I get significant resistance then i re-evaluate/get away from my hand depending on what I have/need to improve. A lot of the time the resistence you get is one card to the flush looking for the last one and the worst thing you can do is let them come along. I am not advicating turning into a complete spewy mess because you never believe the opponent has a flush, but use some thought (i.e. it could be that the flop hit his hand and he is trying to protect it from you).

 Straight draws on the other hand are more common depending on the situation. For tight players if there aren't a bunch of coordinated high cards out there you can pretty safely assume the resistance you are getting is from 2 overs, not the straight trying to protect themselves or draw to a favorable card. For a looser player (20-35% opening range) you have to look at the dynamic a little further. If they are calling a raise IP then you have more decisions to make based on flop texture, but if the situation is reversed I would play hard into them for a street and see what they do, let the action dictate where you are at.

So my rambling aside a little I think the biggest suggestion I have is play your line and then interpret their actions based on what you understand about their play and board texture. There are a lot of times where you can use the exact fear you are expressing against players. I can't tell you how many pots I have been able to pick off lately when 2 cards to a flush come on the flop, I float a c-bet and the third comes on the turn. Flush scare cards are obvious, even to micro players so you can use them as a weapon against them, just be careful to read and evaluate resistance if you hit it.