There are over 750 genera of orchids in the world so when choosing the one for your home, try my simple method. Just buy any that you see available at any store. Most stores (unless an orchid specialty shop) only offer the varieties that are easy to grow under normal household conditions. To name just a few that you may see: Phalaenopsis, cattleya, dendrobium and papheopedilum. These orchids love the average home conditions even if you run your temperatures a little warmer or a little cooler, they still work for these orchids.
These varieties will normally want to bloom in the fall, winter or in the early spring with blooms lasting from only 2 weeks, up to 8 weeks in some situations. The main concerns are with the watering. The general rule is once every 5 to 12 days. That's a big gap but you must decide just how often, based on the time of year, how warm it is and how much light it is receiving. And, how much water to use at any given time is another factor. I think we have all seen commercials for the "Just Add Ice" orchids on television. Well what I have learned from that is simply to figure out how much water 2 to 3 ice cubes would be and to always water with that amount of water. Melt the ice in a measuring cup and then remember the answer, or you could just use ice. Try always to keep the leaves dry, as they will spot and never allow your orchid to stand in water.
Once your blooms die, cut them back to only 1 / 2 " from the base of the plant. If you are thinking of re-potting your orchid, try to wait until spring. The soil that you use should definitely be Orchid Soil as this soil is totally different from regular soil and is a must.
Orchids like small, tight pots so do not go crazy with too large a pot. And the roots that are on top are normal for orchids as many varieties do have them on top, sticking out of the pot. I personally think that these give the plant character.