I would go to Ace Hardware or your local hardware store. Many people there are experts in every house projects, from drill bits to painting aluminum siding! They will be able to help you not only with the aluminum siding, but they'll also help you find the supplies you need!
You can find the best tips for painting Gunpla online at otakurevolution.com.
You can find many great painting tips online. One great website is http://www.popularmechanics.com/home/improvement/interior/4286872.
The biggest source to get tips and ideas for painting furniture and other various household decorations is the Home Improvement Network. The Home Improvement Network covers everything from renovations to painting.
YouTube has excellent videos of Body painting and is great since you can actually see it with your eyes.
Reviews for body painting can be found at websites, such as Cosplay, Mechantcircle and Zimbio. Reviews for body painting give good suggestions and tips for body painting fans.
Hints on painting for kids can be found on a number of websites. A particularly helpful example can be found on the eHow website, with the topic name Painting Tips for Kids.
You can find a guide to oil painting at http://www.guidetooilpainting.com/howtooilpaint.html. You can also find tips at http://painting.about.com/cs/oils/a/tips_oils.htm
Tips on spray painting can be sought at AZ Central, All things thrifty, Amazon, Ebay, Gleem paint, Mustangs, Kitchen Kool, Tipson spray painting, and Rustoleum spray paint.
Many great tips for painting and decorating a child's room can be found online. Perhaps one of the best tips is to pick a theme that they can grow with so it can still work for them as they get older.
HGTV has articles dedicated to how to properly paint panelling. Here is an example of an article: http://www.hgtv.com/decorating/tips-for-painting-paneling/index.html. It stresses the importance of making sure the panels are completely clean before painting.
And the questions get even dumber...I start using q tips but if they are too small i get paint brush tips by cutting off roadkill tails
There are several places you can get tips. You could read home improvement magazines or watch home improvement shows. You could go to the paint department at your local hardware store and ask for advice.