Becoming a tattoo artist may not be as easy as it looks. I am afraid, just being good at drawing or being passionate about doing a tattoo is not enough to make you a good tattoo artist. Various factors work collectively to make someone a professional and famous tattoo artist. I may not pick up all the points, but I will try to present all the possible things that matter.

Image: Trailertrashtattoo.net
All you need to do is just keep yourself open to all the possibilities that may come up on the way. Hard work and persistence are something you need at every point in time in this profession.
Equipment
Knowledge of tattoo machine kits is the first thing that you should look for. Although it is a vast topic to cover, I will be giving a brief idea of what equipments to look for in the first place.
Tattoo Machines
Tattoo machines are basically of two types coil and rotary. You can prefer them as liner and shader. Coil tattoo machines are used mainly by established tattoo artists because this kind of machine is heavy and a little hard to control. They make noise and use more needles than the other one. Even in the coil tattoo machines, there is various kind.
Most modern-day tattoo artists prefer using rotary machines, as it is comparatively light and easy to use. For liner work, these machines are great.
Both have their perks and disadvantages when it comes to picking up the best one for you. If you are a beginner, you can train under other artists and practice to know which one you are more comfortable using.