First, type boat launching into the search topic at the top of this page. There are many great threads about boat launching dos and dont's.
If you are going to practice launching your boat either go during the week or very early in the morning or very late in the evening. You do NOT want to "practice" at the ramp on a weekend during peak hours. You will just slow the process down and annoy seasoned boaters.
For me, I go through a mental checklist every time at the launch. In fact, I used to have it written down in my truck until it became habit. Go through this checklist every time without fail, exactly the same order and you will not forget a plug, a strap etc. I start in my truck once I pull up to the ramp
1. break on
2. unhook chain, unhook winch strap
3. walk down port side unhook rear strap
4. screw in plug and remove jack
5.walk around to starbord side and remove rear strap
6. when walking past captains seat flip on power and accessories
7. at front of boat check the hitch again just in case
8. get back in truck, open both windows
9. release brake
10. back boat into water.
As for opening both windows, this gives you much more awareness and allows you to hear someone yelling at you that you are about to hit the dock, etc.
With practice, you should be able to launch your boat in about 5 minutes even by yourself. If you want a crash coarse in what NOT to do, just go sit at the ramp on a Saturday around noon. Take a few cold ones cause it will be comical.. Good Luck