Create a website, and make sure you have a good veriety of shirts, and maybe pants and caps with prints on them. And next faze is marketing. Banners, flyers adds in the local papers...use your imagination. Don't charge too much, you wan't too sell some in the beigining as a way of spreading the rumor of your sites existence, then gradually bump up the prise untill you notice sales are going down.
What's your current level of sewing? Are you a complete beginner; have you made a couple of garments before; have you made many unlined garments; are you ready to tackle a tailored item?
How easy are you to fit with a pattern? Do you have a pattern you'd like to use that's already adjusted?
What's the level of expertise of your teacher? Is s/he someone who makes their own blazers, or one who remodels t-shirts?
How much time do you have to sew during the class, and can you work at it after class time?
For first garments, I tend to suggest things that can be worn as nightwear... pj pants, simple t-shirts, nightgowns, nightshirts.
For second garments, I tend to suggest something in a very forgiving fabric like Polarfleece or wool flannel (get the good stuff from Malden Mills or another good maker, don't go for the "fashion fleece") with a pattern designed specificially for for the fabric (look at Jalie, Kwiksew, Stretch and Sew for fleece). Something like a vest or swing jacket is good for fleece; simple skirts or a vest with wool flannel. Both of these fabrics can hide a multitude of sewing sins. <g>
Or can you work outside of class, and would your teacher back you up with expertise? If so, you might consider a simple lined blazer or jacket using "quick tailoring" methods, where fusible interfacing is used to build shape instead of pad stitching?
What does your teacher think you're ready for?