What Are The Things Should I Take Care Before Going to Design A Database?

There isn't a "list" as such, it's an experience thing as much as anything.
The important things are:
1) Don't over complicate it.
2) Don't store the same data in two places, use a reference to a different table that holds the actual data.
3) Make sure each table has an ID row - this can be an integer with Identity specification set to true if you want - so that it makes each row uniquely identifiable. It doesn't take much space, and it can save a lot of time.

Then, if you are a beginner, or not too sure try it all out manually:
Start with a pile of blank paper and a pencil, and go through each and every function the userhas to do and play with it on paper. The idea here is to get a firm picture of what data you need to play with and how it can be well organised - you should find that one approach falls over and makes life difficult somewhere else, or a small tweak or an extra table will make things easier.
Try it, test it, and use the paper as database tables. Then when you are happy, do it again - this time with two user doing things at the same time. Causes problems? Can do - and it's easier to fix now than later.

When you have that, design your DB from the paper version and again, try it out using SSMS and maybe a couple of stored procedures. Time spent here pays big dividends later!