Is the banana plant that is arriving a small plant? If so, I would not put it in a huge pot right away. If you do, you will run the risk of rotting the corm. I usually gradually pot them up as they grow or wait till they are a few feet tall to put them in the ground.

Potting soil should be a light mix. I usually use Miracle Grow, Jungle Growth or something similar and add some perlite to it when they are small. Once I start potting up in size, I will add some worm castings or other good compost to the mix.
Bananas are heavy feeders so once you have it potted and if it is showing some new growth you can begin to fertilize it. You can start out at half strength and gradually increase to the recommended dose. If you have it outside during the growing season, they like stuff like manure tea and fish fertilizer (Alaska brand can be found at H. Depot)
Bananas like a lot of water but like to be in well drained soil so make sure your pot and mix is draining well and has holes in the bottom.
There are also fertilizers on the market specifically for bananas that will provide all the nutrients.

When I plant my bananas in the ground, I will put in a few shovel fulls of composted chicken and rabbit manure and also a little Black Cow manure. They grow very fast with this method.

sultry - I used miracle grow potting mix (with fertilizer) to repot my dwarf lady finger banana and it's dying. :(. Does the miracle grow mix you use have fertilizer in it? I can't find it w/o fertilizer locally. I did order pro mix. I hope the plant can hang on until it arrives. I don't want to lose it. I hope this works.

I try to avoid any mixes with fertilizer in them. I have very bad luck with them or should I say my plants don't seem to like it.

I have cows, so I pile the manure up and wait for it to turn into dirt, then mix that with coconut coir, sand, vermiculite and the cheapest potting soil I can find. This mixture is what I use for almost everything. You can substitute the cow manure for any type of compost. Depending on the plant, you can use less sand or more sand. No plants have complained about it yet.

I just got my first banana plants and have several questions about growing them myself.