Tips on editing on Windows Movie Maker
1:Add some effects like Pixelate, Film Age older, and Water color to make it cool
2: Use transitions like Shater In (my fav) and different ones to fit the situation
3: Try not to cut a lot of parts of your video
4: Add tittles and credits and make them colorful
5: Add music in your intros and tittles.
Thats it for now i guess hope this helps