Wyld Hair On A Tangent Group -FULL (Page 13)

They probably look smooth because they've been doing the butter fly for a long, long time.  It's a ridiculously hard stroke to do, but it's also (in my opinion at least) one of the best core work outs around, so that's why I do it. 

First of all, there's the timing of your kicks and pull.  That really just comes with practice, practice, practice and getting stronger.  However, as for feeling like your making huge waves out in front, that might be easier to correct:

If I had to bet, you're probably pushing yourself up out of the water instead of pulling yourself through it.  Your arms may be to straight, going to deep, pushing you up, then you fall into the water making a huge wave.  The best way I can describe it is after you have thrown your hands forward, you basically pull the same way as you would on a free stroke, you just do it with both hands at the same time.  Elbows bent, pulling from the lats, not driving your hand down to the bottom, not swinging out wide either.  It's a funky feeling, but if you practice it a lot, it gets more natural.

It's kinda hard to do, but you can slow the fly down and work on it.  It's really on getting the timing down between dolphin kicks and the "two arm free."  Any up and down movement should be minimal and the result of the kick only.

Wow.  We've actually got a couple inches of snow on the ground.  Everything looks pretty, but the roads are getting crappy.  The drive to work was SLOOOOOW.

Try the pull and glide with a pull buoy between your legs.  The buoy will let you forget about your bottom half so you can focus up top.  Basically, you just really exaggerate your... well, pull and glide.  You take a normal stroke but you hold it for a about a second longer.  So, your left arm is out front while your right arm is at the back end of your pull, and you pause there.  This is a good drill for streamlining and rotation work, but you can also focus on keeping that arm up when you take a breath.  It will exaggerate the amount of time you've got to keep it up there, so you should really be able to consciously focus on getting that good initial "grab."

That is a very, very common thing that your noticing.  I do it all the time at the end of sets.  You just get tired and certain parts of your stroke start to fall apart.  Problem is, not a lot of people notice it, so they never really get to work on it.