If you want to get better at graffiti I would recommend grabbing a good old pen and some paper. Then practice for a few years. Especially for handstyles (tags) it takes years of practice to get a good flow like Bates handstyle
here for example. Look at what masters like Bates, Revok, Rime, Seen, Daim (to name a few) are doing and how they structure their letters (but never ever copy their style). Start by doing simple block letters to fully understand the structure and then later move on to more advanced styles like wildstyle or 3D if that's your bag. Try to develop your own style as it's a must to have an original style in graffiti.
Here's a little bit of inspiration for you..
www.greatbates.com <--Danish Quality
Classic New York Style Graff
http://www.daimgallery.com/ <--3d master.