Spell checker would be a good start...
I have to agree with Dr Buck, spelling correctly or at least using a spell checker is going to help you no end if you do decide to become a trader. There is a spell cehcker called iespell for internet explorer and most likely similar for other browser platforms too to help you, after all none of us are perfect at spelling.
I would certainly think twice about using someones service if they can't spell or be bothered to ensure their spelling is correct, also you may want to think about the name, does it mean you only work on MG's or MG and Rovers as some may think you only do work on MG's even though they are the same engines.
As Kayleigh also pointed out your user name most likely contravenes the forum rules at this moment in time. And you need to look at the subscriptions page for the options on becoming a trader as mentioned.
You would ideally also want a website assuming you haven't got one yet, with your contact details and location, having a page that explains who you are, what you do and your background on car repairs will also give people valuable information to make a decision on whether they would use your services and some previous cutomer testimonials too.
Do you have appropriate insurance to cover you for doing this work, are you mobile or not?
What items do you use to fix the HG on a K series etc as people on here know the engine very well and most won't use you unless your using the correct gasket etc.
All things for you to think about.