the best advice I got for the arms is to reach as far as you can ABOVE the water. The hands should go into the water when your arms are pretty much stretched out full. The less contact the arms have with the water, the less resistance. Also translates to less fatigue in the long run.

Try doing some drills where you basically just stretch out as far as you can and basically coast for a bit. Tuck your chin in, and try to get a longer stroke out of it rather than increasing the turnover. Try to get a bit of a cadence like you're ice skating - streeetch, stroke, streeetch, stroke.

You've got a great kick, so all you need to do is just fix the arms!