1. Prior preparation prevents poor performance! This is actually crucial, always prepare your surface before you paint! Remove any imperfections, old paint, uneven spots, etc. Whatever you can do to prepare the surface, do it! The work you didn't do will almost always show through the surface
2. Use a primer, there are many available for all different surfaces (wood, metal, plastic, etc.) and are key to a great paint job.
3. Shaking the can is really important. Shake the can for at least 2 minutes. This will ensure all the paint is well mixed before you paint! Not only that if you're painting a large area keep shaking! Turn on some music and shake that can like it's a maraca and you're in a mariachi band!
4. Prop up whatever you're painting off the surface it's on - if what you're painting is flat make sure there is a gap between the surface and the object. This will prevent the object from sticking to whatever it's sitting on and potentially ruining your paint job when it dries.
5. Hold the can 30cm from what you're painting and use even sweeping motions - this is important because a buildup of fine coats is what you want rather than trying to spray it on all at once which can cause ugly paint runs and uneven spots.
6. Make sure you paint somewhere that is clean, the spray can actually kick up debris from around your painting area and find its way onto your nice new paint surface!
7. Try not to breathe in the fumes, they actually don't smell that nice.
8. Don't touch it! Resist the urge to pickup what you've painted until its actually dry. I can admit i'm very guilty of this, "dry faster so I can admire my work!"
9. When done hold the can upright and spray out until the paint stops flowing - this will prevent the nozzle from clogging and ensure you can keep using it at a later stage!