Be sure that you provide valid contact information. Your domain can be disabled if someone complains that your contact information is incorrect.
Don't let that domain lapse. Be careful not to let your domain lapse. Otherwise, unscrupulous people may buy it and then try to sell it back to you at a profit.
Lock your domain once it is set up. All registrars should permit you to "lock" your domain. The reason you want to do this is because you can lose your domain by not answering an email from ICANN within 5 days if your domain is not locked. Do this after setting up your nameserver information. You can lock and unlock your domain at any time, though the change may not be instantaneous.