Here is some random advice I can think of, in no specific order:
You definitely should look into taking additional certification classes that your school offers besides the CMT/LMT. I don't know what courses your school specifically provides but if possible I highly recommend taking courses related to your wanting to help people with injuries such as Deep Tissue, Lymphatic, Neuromuscular and Sports Massage. These will provide you with knowledge on how to treat a wide range of injuries and skills to take to any spa/studio you may work at.
Depending on what (if any) specific types of injuries you want to treat you should look for a job related to them. You could look into working for/with a chiropractor, local college sports team, physical therapists office etc.
Get business cards and hand them out EVERYWHERE. Grocery store, restaurant, friend's house, mall, anywhere there is someone with an interest/need for a massage. There are lots of practicing massage therapists out there and you need to have your name be known.
I have found that once the words "I'm a massage therapist" come up in conversation people usually express interest in getting a massage for themselves or a friend/family member. For this reason always have business cards on you! Keep them in your car, wallet, purse, locker, pocket, EVERYWHERE. There may come a time when you miss out on gaining a client simply because you did not have a business card to hand to them.
When some people hear "massage" they think of "erotic/sexual massage". Go with your instincts when screening potential clients/giving someone your card. I have made the mistake of giving someone my info even though I wasn't too sure that I would be comfortable working with that person and it turned into a small nightmare for awhile. Never put yourself into a situation where you are uncomfortable working on a specific client but are too shy/nice/afraid/whatever to tell them you are unable to have them as a client anymore.
If working for yourself: establish how much you will charge clients and make known what types of payment methods you accept. Not everyone carries cash on them all the time so you may want to invest in some type of mobile debit/credit card reader. It makes things much more convenient and less awkward when you have to turn someone away simply because they do not have cash on them.
In my opinion, word-of-mouth advertising is the best form of advertising. People are more inclined to go with someone who was recommended by a friend/family member than just a random business, you will reach all types of people you never would have thought of and its free.
I have found that "trading" massages is a good way to gain new clients and get word-of-mouth advertising. I have had successful trades with a hairstylist, photographer, baker and mechanic. The first person I began a trade with was a hairstylist friend of mine. She'd cut my hair, I'd give her a massage, no money involved. Her co-workers had heard about our trade and that I was a massage therapist, so when she was cutting my hair they'd express interest in getting a massage for themselves/friend/family from me. Suddenly I had paying clients, free advertising and free haircuts from my friend still.
Some friends and family will assume that they are entitled to free massages now. It's up to you to decide if/who you are giving free massages. Friends and acquaintances constantly ask me for a massage and with some people I throw in something like: "Sure, I can do an hour for $(whatever you want to charge) if you want." You paid for your training, worked hard and this is what you do for a living now. People need to respect that and not treat you as if what you do isn't all that special.
Take care of yourself! I already wish I had paid more attention to my posture/stance/discomforts while giving a massage. You'll save your wrists, back and more just by taking the time to do things properly.
Hope any of that helps you out :)