lol thats funny you ask that.find your most ghetto wall and train and go take the chance to practice there.

Honestly, I do not think most of the people who make graffiti have attended Parsons School of Design or the Chicago Art Institute either. I think it is a matter of painting and designing what comes to your mind and pleases you. I assume you are talking about artistic graffiti that is sold verse gang painting or graffiti on subway walls.

you could try http://www.graffitimasterclass.com/

first you must study graffiti style, graffiti history and get inspiration from other artists. while you do this, experiment on letters. do this for 1 month or so. then create a name. something short like skram, selk; anything with good letters and sounds so good that you wish it was your name. dont have the name with all good letters like skrl. i know they are good letters but its suppost to be like a name. dont put your real name or a proper name. you dont see a tag that sez, john, tony, etc. ok now you have your name. you get like a sketch book and write your graffiti name. if you think it looks toy or unpleasant, try experiment your letters. aim to get your letters flowing. this should take a month or so. when your pleased with your name, work your way up by putting your tag (your name) on the streets just for an experience. do this for one day cuz i dont want you to get caught graffing. choose a hidden spot but can be easily seen from a particular angle. then when you come back home grab your sketchbook and design a throwup or bubble writing style. its not simply bubble writing but has a style to it. look at throwups and compare them to simple bubble letters. try to start from simple bubble letters and modify them to your satisfaction, this maybe frustrating as this could take a while. after creating your throwup. use all your studies and inspiration to put together a piece, or those really intricate graffiti work. a good way to start is block, 3d letters. dont go onto connections, extentions, or other advanced details. just move to fillins. fillins are important. if you watch graffing videos they make the outline first and put the main fill colour with the same or different colour as the outline. the first outline is not the official outline for the piece. its like a reference. now after you filled your outline with your main colour, put some details into the fillin like a secondary fading color on the bottom, or bubbles or scribbles, anything that looks good and attracts attention. now after putting your fillin details you outline the letters. this can be hard as you might not remember where the letters are due to the fillin. thats why it is importnant when doing it in real life to have a sketch to copy off or the first outline in a different colour. now for extensions, details and advanced lettering. make them flow. arrows are good way to create the illusion of flow, but not too much. variation in lines in your letters and details is important to have that great look to your piece. details like reflections, shadows, outlines, etc are good. ohh. i forgot. your equipment. spraycans and thick markers as your tools. bags with hidden areas for storage, face accesories for face disguise if going public, and a good fitness level for running away from witnesses. when you go public be sure to have an observative eye for witnesses, security cameras, etc. always hide your face with a bandana, cap, and hoodie. if you are spotted from far away run as fast as you can to a hidden spot, if you are spotted from 5-10 metres, run and keep 1 spray can in your hand as a weapon. if you are spotted at real close range or you are being held, have your spraycan at the ready, and spray their face. you may feel bad but remember, graffiti is an art and a way to express your self so dont let anyone stop you from graffiting. if a witness sees you but you are in a difficult tight position. act peacefuly with them ONLY retaliate if they decide to physically hurt you. if they call the police, run from the scene. where not to tag: near your house, in big private areas, police stations (but police cars yes), your belongings, etc. rules for graffiti: dont act hardcore and smash stuff. graffiti is enough. respect peoples property. only graff on public property. dont copy others work. dont go over a good piece or artwork dont go over murals (those rememberance graffiti) thats basically it. ohh always ask for help from more experienced artists. keep practicing and soon youll be great!!

what the guy on the top missed was, get involved in your local graffiti culture, you may get to know some older writer(s) who could teach you more than you can ever learn by yourself.

Practice in your school bathroom and on books people leave around ...