This article was originally published here.
DO'S
1. What to do when the strings of the racket are broken?

a. Strings are subject to wear and tear. It is very common that strings break while playing. To increase the life of strings always keep your racket in a cover safely while not in use.

b. If the strings breaks, cut open all the strings because even if one string is broken the tension in the strings is distributed unequally that puts extra pressure on certain points on the frame and hence will change the shape of your rackets head.
2. Getting your racket strung

a.If the strings of your racket are broken or lose you should get it re-strung by a professional stringer. Always use good quality multifilament strings and replace the grommets in case they are broken or missing to avoid strings getting cut by the edges of the eyelets on the racket frame.

b. String tension should be in the suggested range and in case of an old racket ask your stringer to suggest the string tension.
3. Replacing the old grip

a. Rackets come with a base grip which is pasted on the wooden handle and depending on the usage, grip gets damaged. In order to maintain a good grip between your hand and racket you should replace the base grip every 2-3 months.

b. To protect the base grip or to have a thicker grip depending on the size of your hand you can also use an Over grip.

DID YOU KNOW: If your palm sweats a lot you can use a towel grip 
4. Proper storage/carry

a. Graphite rackets are very strong and can take high tensions but if not stored properly in a foam cover, the racket is prone to external damage and the durability of the frame reduces. In order to keep your racket frame safe always keep the rackets in a foam cover.
DON'TS
1. Shuttle hitting the frame

a. While playing with a racket if the shuttle hits the frame the frame can get damaged, Especially during a smash. Hence if you are a beginner always use a metal racket because they are more durable, once your play level improves switch to a graphite or high modulus carbon racket and try to avoid hitting the shuttle with the frame of the racket.

2. Racket Clash

a. While playing doubles make sure not to hit your racket with your partner’s racket as graphite/carbon rackets tend to break in case of a clash and steel/ aluminum frames tend to bend in this situation.

3. Storage Of Racket

a. Never put any heavy or pointed object on the racket. Any unwanted pressure on the racket can change the shape, flexibility, and strength of the racket.

4. High Temperatures

a. Graphite and high modulus rackets if kept in sunlight or high temperatures will start melting and thus changing the shape and drastically reduces the strength and durability of the racket.

5. Higher String Tensions Than Recommended

a. Higher string tension than recommended or high string tensions in old/damaged rackets will make the racket frame to bend or break during the course of your game. Hence make sure that the string tension is in the recommended guideline.