This varies with species but most will eat and do fine on a once a week feeding schedule. As stated before people tend to overfeed their snakes. Try not to panic when one takes a couple of weeks to start eating. They are cold blooded creatures and they just don't need that much food.
As a rule of thumb I try not to offer anything that will stress
the snake too much when feeding. For example a 3 foot
These are mites and you have stumbled upon them. Mites are a problem that most herpers try to avoid but eventually run across at one time or another. Mite exist everywhere and the many ways to transmit them to your collection are surprisingly easy to do. You can get mites from something as simple as putting a piece of decoration from outside in your container without washing it first. You can bring them home from the next reptile show you attend, surprisingly without even touching a snake. The little monsters will get on your clothes and hitch a ride home to your pets.
The easisest way to get rid of them is to allow the snakes container to dry out. The mites
Your snake's set up can be as simple as a plastic sweater or shoebox or as elaborate as you can afford. The decorations in the tank seem to be more for the owner than the snake itself, most of them don't seem to care if there is anything other than a water bowl and a place to hide. On the size issue provide your snake with at least enough surface area to make two and a half times the size of the snake. In other words they don't need room to jog laps but they do require enough room to stretch out comfortably and move around while digesting food. Larger containers also make it easier to set up a thermal gradient allowing the snake to choose the temp that suits it best.
1...2