How to transplant orchid into a bigger pot?

This is actually serendipitous because I have an orchid that has been doing really well, but I would like to transplant it into a larger pot. I’m afraid to mess up though because this is the only orchid I’ve ever had that’s lasted longer than a few weeks (I got this one in February!).

What size of pot do orchids like? What do I use as potting material?