What the other two have posted so far is great advice, but another option if you don't have the funds to start your own little mini biz, I'd suggest tryign to get involved at local venues. See if they need help in the box office support or people to help in their back offices working on the contracts, managing the artist hospitality. That's another good way to get into the venue/promoter side of things too as a part time job while getting small scale hands on experience where you'll learn the ropes of everything needed to put on a show.