With voice acting you would need to practice and hone your art in using your voice. Always remember to do warm ups because one's own voice is very fragile. General tips would be to practice acting in general. Practice trying to make yourself be in the position of the character and make their voice sound realistic as if the event is actually happening. Some VA's do a great job at it and while they are successful, that is due to their delivery in their work. You would also need to have decent equipment (such as a decent quality microphone, audio interface, location to record, etc).
Starting in voice acting you will probably want to record a demo of yourself and the many different types of voices and roles that you can do. Doing so will show others the skill and talent you possess as well as giving them a sample of what type of voice they can expect for their project. Try audtioning at many different projects. Doing so will at least give you more experience and will help you land better jobs later on.