Hi I Need Some Help With Veins, Arteries And Nerves..

Hi I need some help with veins, arteries and nerves.. For iv use.. How easy is it to hit an artery instead of a vein? (For arms and ankle area) for someone who has not much experience. Also are nerves possible to hit using a seringe? Is there an advice you can give for someone who has to IV's themself for getting in the vein and not missing?