I have recently obtained a manicure/pedicure certificate and am about to do an extensions course, with a view to setting up my own mobile business. I would love any advice anyone can give me on setting up on my own, getting practice, whether I should train in acrylics, gel or fibreglass. Any words of wisdom would be greatly appreciated!!

The best thing to do is get the best education you can this is going to cost you but you will never look back, Once qualified practise on friends and family get you speeds down and then go mobile.
You will need to buy all your stock first and get flyers, business cards etc printed.
8 out of 10 of my clients would have l&p the rest gel nobody ever asked me for fibreglass.
hths

I'm not going to repeat leli's advise, just add to it.
Get the phone book out and ring all the nail techs and tell them you are doing a bit of market research and could they tell you what % of clients have L&P, gels etc. My area is mostly L&P but they love their gel toes.
Stock up on what you need and stay away from what you want, its so tempting to buy loads of goodies. Buy good quality products, they pay for themselves in the long run and save your reputation.
Have good insurance. Advertise that you carry full insurance.
If going mobile, before you start buy a map of your area. Work out how far you are willing to travel and get to know all the minor routes through all of the area you will cover, nothing worse then being stuck in traffic if by taking the next turn you could get through and be on time.
Talk to your bank about a small business course, these are usually free and teach you the basics of cash flow etc.
Put money aside each week for your tax bill and for more training.
Speaking of tax bill, register your business within 3 months of your start up.
If I think of any more I'll come back to you.

Thanks Guys, that's all really helpful and much appreciated.