Hey I'm doin the same thing and have a shop waiting on my school schedule to work itself out before it 'officially' hires me. Find the one you really want to work at, ask for the owner or highest manager cause you want to talk to him. Tell him that you absolutly love car audio and doing installations and have done a few for your friends but nothing professionally. Just sound real excited, really motivated to get the job and the key is to make him know that. tell him that I'll suffer through the ***** work and love working with your hands and watching a project take shape. Hopefully, he takes your name and number and says he'll think about it. This is when you call almost everyday touching base with him and proving to him your motivated and really want the job. After a week or two, it might take hold and he'll give you the job. This worked for my job in a performance garage and is working for and audio shop. Don't lie about your experience though. If you tell him you can do headunits, he'll expect you to be able to install a headunit no problem. I told the owner of the shop that the only thing I'm shaky on is removing door panels because I'm afraid to break something. It shows a touch of finess. Hopefully this lil "tutorial" can work for you. Good Luck.