Well that a pretty massive topic, but I’ll take a shot at it. I’d say the most important thing is that you have a group of people who you can feel comfortable around and have a good time with. A band is sort of like a marriage between many people. You have to respect everyone’s ideas but also you have to make the best decision for the group as a whole. I’ve coached a lot of bands in my years teaching, and many times I see ego getting in the way of progress. If you and all the other members can check your egos at the door, and not get bothered if one doesn’t like your idea etc. then you should have an amazing experience.
The best way to begin a band is by starting with one other person that you can write music with. Whether that’s a drummer or singer or bassist or whomever, it’s important that you both not be judgmental, but rather nurturing. Most ideas, when brought to the table aren’t polished and should be given their fair shot in the song. Try writing with someone and see what kind of ideas you can come up with. It usually starts with one person jamming on a riff or chord progression and then it should flow naturally from there. The great thing is that there is no set rule to any of this, and it’s all up to you. So find a friend who plays bass, or sings, or just grab a buddy and tell him to get a pot and spoon from the kitchen…make some music with a friend and that’s the beginning of your band, how far you take it is up to you!