A lot of singers on the national scene sometimes spend days in the studio singing just one song. Their producers have budgets that allow them to edit 100's of takes into a final compilation performance. First, spend some time before you record rehearsing. Before recording your music, it might be beneficial to find a vocal coach to work with you to give you extra confidence. The better your preparation, the more polished you'll sound on the master.
Every great singer knows that singing is part attitude.
Why not bring along a couple of your trusted friends to sing to. The jazz group, Weather Report, recorded before a small audi ence in the studio. You'll perform better when people who appreciate you are along. A good producer will help you find your comfort zone to sing. You should trust your producer to tell you when it's good and when it still needs work.