You have to look and do your work (I'm hesitant to give away my secrets) if you are only looking at the top 30 guys and moving them around then, yes. You are wasting your time. I have been very lucky that in both of my leagues I have been picking 20 or lower every draft and every draft I end up getting a kid that will be useful on my team.
You have to temper expectations. If I'm picking top 10 I look to get an everyday player or front of the rotation pitcher. 10-25, a bench guy or a 3 tool player and a back of the rotation starter / ace bullpen guy. 25+ I'm usually looking for a bench player that does one thing really well (defense, hitting vs lefties, base running) or as good a bullpen pitcher as I can get that will only pitch 40 to 50 innings.
You have to look deep and be willing to take a chance. Rather then letting the draft board dictate where my players should go I sort them by the categories I feel are most important and then rearrange. Sometimes I move guys up 100 spots on the board. But as I said, it works out.
When in doubt, scout College for picks 15 or higher and HS 16 and lower. College kids are less fuzzy but because of that most people know they are good. HS kids are fuzzy as heck but because of that you can often get a gem in the later rounds.
Examples of all of the above:
Johan Butcher drafted 26th (HS kid)
Alex Hunter. Drafted 26th (college kid)
Omir Ewing Drafted 23rd (college kid)
Gregory Goldman Drafted 73rd (HS kid)
Brent Hammond Drafted 23rd (College kid)
Red Dewitt Drafted 53rd (College kid)
Nico Thompson Drafted 51st (college kid)
Remember also its baseball, not basketball. I would prefer 25 serviceable players that work well together rather then 2-3 all stars and then all crap on the back end. Do the work and it will pay off.