I first didn't have in mind to give instructions on how to decorate a bicycle so i don't have pictures of every step but i will explain with the pictures i have.
I do have to warn that this project takes a lot of time but the end result is worth it.
(i won a contest with this bicycle :p )
First step disassemble the bicycle so you just have the bare frame.(remember or write down where everything came from you will need it when you reassemble the bike).
Remove the paint of all the parts that you want to paint.
Step 1: Painting your parts
Next you clean the parts so there is no grease or dirt on the bare metal parts (dish washing soap will do) and dry the bike.
Be sure not to touch the cleaned bike with your bare hands because your hands have grease on it also.
1. Apply a light coloured primer (for light blue a light primer is best).
2. Apply your colour coat and remember to have an even coat and that there are no drips or white from the primer.
3. (optional) apply a clear coat so your colour coat is protected from scratches.
My personal opinion is that spray cans that are a little bit more expensive will give you a better result.
Also what you have to do is have patience between the layers (it's better to wait a bit longer then screw it up because you where over anxious ).
One more hint : read the instructions on the cans they are there for a reason and tape of parts that shouldn't be painted.
If all whent well your parts should look like the ones in the pictures