Some tips can help you:
Pursue degrees in communications. Some types of communications degrees can help radio presenters and other broadcasters to get access to a greater set of jobs or positions in the industry.
Create a demo for radio stations and other potential employers. After having collected some experience and getting used to the idea of presenting on the radio, as a career-minded individual, you can set up a demo presentation that you can show to representatives of larger broadcasting networks.
Develop connections and a professional reputation. Some of the most successful radio presenters, for example, radio talk show hosts, have had a long career including extensive networking and brand development.
Cultivate a good radio voice. if you want a long standing career in vocal work you need to look after your voice and you need to pronounce with great clarity. Get voice coaching lessons if possible. It is also important to find some vocal warm up exercise routines, to preserve your voice long-term.
Buy (or borrow) a microphone and a recording device like a mini disc player. It is important to record and listen back to your voice as you can then hear how everyone around you hears your voice.
DJ'ing at discos and small functions can be a great learning experience on how to cater to a specific audience which radio is all about.
Find a place to present as a volunteer. Volunteer opportunities will gain you lots of experience and you'll get good advice from those already working in the industry.
Start your own internet radio show. There are now many free facilities on the internet which help you broadcast your own internet radio show so they are now very easy to produce and, even better, they're very inexpensive.
Get a computer with an audio editing software package, when you have refined your vocal skills you can start producing your own radio shows from your own home.