Ways to increase blood flow in fingers?

Okay, so I want to grow my nails out longer because I like to create nail designs on them and it is very hard to do designs with extremely short nails. (Im only a tween so typically I have short nails) I already take extremely good care of them by applying cuticle lotion on them and using Sally Hansen's Nail growth Miracle. Plus I do the manicure stuff and I keep them clean due to my OCD (: Anyways, I saw that in order to make your fngernails grow you need to increase the blood flow throughout your fingers. Can anyone please give me any suggestions? I already know that typing, texting,and playing piano helps... any other ideas? Thank you! :D