The way you wrote it I'd assume you're not extremely experienced in poker (just assuming here of course) so I'd suggest you to do some starter course in poker first, this page also has one. After that look at some pre-flop charts and ranges. Only after than you can play up to the competition and incorporate their range into your play. It comes with practice and experience.
To simply put it, yes you will fold many hands that would be nuts once the other cards drop, but that doesn't mean you made a bad play by folding those cards before flop. More often than not, cards like for example 74o won't hit anything and you're just wasting your money by playing them. At the same time hand like AKs might not hit a lot of times, but even if it doesn't it could still be way ahead and you'll have easy time betting with it even post flop.