EVP,
Evo gives good advice - you must get the speed right. But don't fixate on the ASI! I know that sounds like a contradiction, but bear with me...
You should have flown enough approaches by now to know the correct attitude on final. The trick is to fly this attitude! If you do that, the speed will be right - you can glance at the ASI occassionally (every 3 or 4 seconds at the most) to confirm, but you shouldn't need to make anything except the smallest changes.
Not convinced? Ok, here's the theory part. We know that speed and angle of attack are pretty much interchangeable in straight flight. So what you really need to do is keep the angle of attack right. And, ignoring any nasty winds, for any given vertical speed, each attitude will give you a specific angle of attack. So if you learn the attitude, and fly the attitude, the speed will follow.
All it takes is practice - keep at it! Good luck,
FFF
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