Commit to a regular physical exercise regimen to improve your conditioning and aerobic fitness. Many aspiring vocalists learn quickly that singing requires considerable physical effort. Inefficient breathing, where the singer is unable to maintain sufficient air in the lungs, leads to notes that fade or trail off and rapid, unnaturally spaced breaths. If you're physically fit, your breath control and stamina will improve accordingly.
Relax. If you're tense and trying to force your performances, it will show in your vocal tone. If you find yourself with your shoulders up high and your neck tensed, gently let your shoulders drop until you feel like you have a more relaxed posture. As you relax, try moving as you sing. A little body sway in time with the music promotes relaxation, helping you feel the groove of the song and deliver a more natural and heartfelt performance.
Record your practice sessions. Listening to your singing will give you an accurate representation of your singing voice, making strengths and weaknesses readily apparent. Listen closely to hear if your voice loses power at the end of each line. If so, you'll want to work on your breathing so that you take in more air when you exhale. Pay attention to your overall performance. Sometimes, a singer concerned with vocal accuracy will neglect to inject feeling into their performance. Although the pitch may be perfect, it can sound sterile and without emotional power.
Examine the volume at which you sing. If you're singing too softly, your tone will suffer and the delivery will be lifeless and dull. If you're trying too hard and singing unnaturally loud, you're liable to lose control, and your pitch will suffer, usually resulting in sharp notes. If your singing volume is right, your vocals will sound less forced and your delivery will become more smooth and accurate.
Work on your microphone technique to make use of a song's dynamics. On quieter passages, moving closer to the microphone will promote a feeling of hushed intimacy which can be effective, while louder passages sung at full volume close to the mic will distort the signal. With a little practice, you should be able to continually adjust the distance between your mouth and the microphone based on the changing dynamics of the song. This should also minimize annoying vocal plosives (pops) and sibilance (hisses) and help you deliver a more polished and professional-sounding vocal.
Become familiar with how a graphic equalizer (EQ) works. If you have a computer recording setup, or even your own PA system, experiment with the EQ controls and study the effect they have on the tone of your voice. Expert use of EQ can mean the difference between a dull vocal sound and a sparkling one. If you know the specific frequencies at which your voice needs boosting or cutting to sound its best, you'll be able to request these EQ settings at every show you play. This will help you to sound good, and it will make the engineer look good in the process.
Learn from the best. Whether via recordings or live concerts, listen to the best singers in the business. Study their phrasing, timing and sense of dynamics and try and learn from their strongest points. Don't be too concerned with copying their style and losing your artistic identity. Unless you have an identical-sounding voice, you will still sound like yourself. If you're able to emulate the vocal styling of experts in different genres, it will make you a more complete singer.