I recently discovered alcohol inks for painting. They are a very different medium and there is not a lot of control using them. 
That sounds fun! What sort of things do you like to paint with alcohol inks?
I like to paint flowers mostly as it's easy to have a loose interpretation. Using them paint beach scenes is fun too. 
Do you need to use a certain type of canvas for that?
Anything that is non porous works great. I personally, like to use porcelain tiles. They are cheap and you can get them from any home improvement store. Haha But, you can buy special non porous paper from any arts and crafts store as well. Do you paint at all?  
I love the idea of painting porcelain tiles! I paint a little bit but just super casually. What do you find the most difficult about using alcohol ink? It sounds like blending it might be a little confusing. I'm sure it takes practice to determine how the different colors mix together?
It runs...but that's what makes it fun and frustrating at the same time. There are medium thinners you can buy that will help alter the colors as well, make them lighter or help blend. It's like doing paint pours, but with ink and on a smaller scale. Alcohol inks are great for causal hobbyists. It's relatively inexpensive and you can find loads of videos on Youtube about it as well. 
That sounds kind of similar to water color painting in a way, in that you have to deal with it running and figure out how to blend it. Are thinners difficult to use?
Yes, it is much like water color, but the inks will blend together much easier. Not at all. You can pour them directly onto the painting or use a small spray bottle to make different patterns. I have used canned air to paint with. I drop some ink on a tile, spray it with the air, might use the thinner to get some different results, spray with air again...repeat. Using a paint brush works well too. But most people just use air or tilt the substrate to get the desired results. 
That's super interesting! What other tools do you like to use in your paintings? I've read that people can use felt applicators to get a marbled look, or canned air to get some interesting abstract effects. It sounds like a really fun medium to experiment with and see what you end up with.