For singers and actors, whether professional or amateur, proper vocal training can make all the difference to outstanding performances. Familiarize yourself with all that proper vocal training entails, from warm-up exercises to physiology, from finding a coach to tuning your "instrument".
A "warm-up" is just as important for singers as it is for athletes. You wouldn't run a marathon without getting your muscles loosened up and the blood pumping. In the same sense, your physiological vocal apparatus needs to go through some preparatory exercises before you get into your usual practice routine.
Ask five singers for their top tip, and you're likely to get five different answers. However, a few tips do regularly appear on "top ten"-style lists. For example, most serious singers avoid shouting, whispering or otherwise straining their voices.
Vocal health may include many components. For optimal health, you should practice good vocal hygiene, avoid strain or "vocal overuse" and follow some simple practices, like staying hydrated.
Voice training may be appropriate for singers, whether for professional preparation or simply for fun. Finding a good vocal coach comes down to both the teacher's expertise and your own preferences for particular vocal training methods.
While there's no substitute for vocal training in person, you can also deeply improve your singing and speaking abilities through online resources. Many professional organizations, schools and non-profits offer in-depth materials to the public, free of charge.