Violin Care
The rule of thumb for your instrument is never place it in a place that you wouldn't want to be. For example you never want to leave it a hot or cold car, over a heater vent, in your unheated basement etc. So if after class you go to the grocery store, or out to eat you don't leave your instrument in the car, it comes with you. Your instrument's wood and the glue that holds it together is very temperamental to fluctuations in temperature.
How to take your instrument out of its case:

Make sure that your case is right side up and always open up your case on the floor.

Open up your case, some of you have locks, some have zippers.

Tighten your bow with the silver screw at the bottom of your bow. Righty-tighty, lefty-loosy. You want to tighten it enough so that only a pencil could fit between the hair and the stick.

This is what your bow should look like when it is tightened.

Grab your violin by the body (not just the neck) and pull it out of your case.

Put your shoulder rest on your violin. The bigger side should go underneath your chin rest.

This is what it should look like when your shoulder rest is on correctly.

Rosin your bow by pressing the rosin firmly to the hair and swipe up and down the bow hair. You should swipe the hair 5 times for every 2 hours of playing. Make sure to place your thumb over the metal square to make sure that your rosin doesn't chip off. Also make sure that you do not touch the horse hair. The oil on your skin makes the horse hair dirty and harder to play with.
Cases are either open or locked, never ever just closed.
When you put your instrument away take either a hankercheif or a microfiber cloth to wipe off the rosin dust from your instrument and the stick of your bow.