The first thing to do is apply for Unemployment Insurance. If you delay, you can potentially lose weeks of unemployment insurance benefits.
Be careful about maintaining your psychological and physical health during your period of unemployment. Make sure you get the support of your family and friends.
Don't use your credit cards unless you absolutely have to. Until you are re-employed, you may become unable to make the monthly payments. The added worries of accumulated debt or bad credit will make it harder for you to concentrate on getting another job.
You can contact your creditors such as credit cards companies and banks and let them know your situation. Some of them may arrange with you for reduced payments for some period of time while you are looking for work.
If you have any retirement savings in 401k or IRA accounts, resist the temptation to access them while you are unemployed. There are severe tax penalties which may apply if you withdraw funds from these accounts before you reach the designated age.