i want to repaint my boat trailer just need to know how do i go about storing my boat well i do it

If you have access to a slip for a couple days just launch it and park it at the slip till you get it painted. If not you can do it like I did. I just left the boat on it and masked off the boat.  I then sprayed everything with rustoleum and removed the masking. 

How big is your boat? You could get some bales of straw, slide your boat on top of them, and throw a tarp or cover over your boat while you work on the trailer. Then when you are done back up the trailer in front of your boat and winch it off the straw back to the trailer.

Make sure it's legal to do so first, but this is what I do....

Go to the launch on a day when it will be empty (I like big launches with multiple ramps and docks so I won't inconvenience any other boaters.) Put your boat in the water and tie off to a dock. Lay down some visqueen and pull trailer onto it. Pull out cordless drill and wire wheel and hit any areas that may have any rust with the wire wheel (be careful around your wiring.) Prime with Rusto spray paint. Usually by the time I work from one end of the trailer to the other I can start to finish coat the part I first started on. Use Rust-O-Leum spray paint in gloss or semi-gloss to finish coat, do 2 coats and be sure to get the insides/bottom. Clean up your mess and put it into a contractor bag. Go fishing to give the trailer time to dry completely. Done. 

Pro Tip: If it's a windy day, you will want to detach your trailer and park your tow vehicle far away from it before spraying any paint.

16ft skeeter ss90 trailer needs a overhaul to match boat

I did this about 25 years ago. I purchased 2 styrofoam blocks(approx 2'x2'x6') at a salvage store to remove a 17' Procraft. I jacked up the boat with a floor jack and placed the blocks under the boat then pulled the trailer out from under the boat. I did it with the motor attached, just trimmed up. Although this sounds a little scary now, I do not recall any problems and I did it alone in my garage. The styrofoam I used were frequently being used for boat docks and archery shooters for targets and not very expensive. I too, was refurbishing a trailer. As I remember, the boat sat that way for about two weeks...Reloaded the boat the reverse way but with help...

Easiest way would be if you have access to a dock overnight. You can leave it there while you get to work and then give the paint enough time to dry. I know at some of the boat shows I've seen them sitting on some old tires. Given that your hull weight is only about 800 lbs you might even consider taking everything out that you can and giving a few strong friends a call.