I'd recommend making business cards, then hit up car meets and shows like you said. Go up to people and say
"That's a really nice ride... My name is Nate - *pass business card* If you need to do any work, give me a call and I'll hook you up with a discount. Pass the deal onto your friends too."
Then hold true to your word and give him discounts. It might sound weird to talk about cutting people deals before you ever open a shop, but this is the way you get customers. This will get people in your shop, get money flowing, and more importantly, get word of mouth flowing. The car community is a social community. The guy you meet is going to go back to his club and say "I got this sweet deal from Nate at "Car Shop". He said he'll give our entire club a 5% discount on any work we need done.
Now when they come in, you make sure you show them what they would have payed, and what they're now paying so they're reminded, once more, how badass you are.
Once you get a little money, it's time to advertise. HIt up the radio. Not advertising is a huge fail on the part of many business owners. If people don't know about your business, you can't get customers. It's difficult to sustain your business on word of mouth alone. Spend some money to make money.
One last point - Before you open up your own shop, go visit other shops that will likely be your competitors. See their customer service, their decor, their pricing, their deals, their products, etc... Then think "This is a nice shop, but it would be cool if they had ____". Find that special something that can make your shop stand out from the rest... whether it's an attractive logo, a catchy slogan, deals on parts/labor, decorations, rare parts that are in high demand (I know it's impossible to find JDM parts in my area), whatever. Just figure out what it is, crunch some numbers (Important!) and find out what can set you apart.
The ultimate question is "Why would people choose my shop over the one they've been going to already?" This could be as simple as - They have attractive deals; Nate introduced himself to me and now I know the owner personally; I can buy JDM parts without having to buy online and wonder if I'm getting scammed, etc...
Think. Plan. Crunch numbers. Analyze. Decide. THEN Act. Business aren't doing so hot these days. The more prep work you do, the better chances you'll have with success.