Congratulations for attempting to turn your hobby into a business, it is hard work to do and many people I speak to in exactly your position do give up very quickly.
As someone working as a professional, perhaps I can give a little advice.
The first thing is to decide - are you looking to run a business to make a real income or are you charging for research to just to subsidise your own hobby, which many do, whether they acknowledge it or not ?
There are very few professional researchers who make a full time real living income from genealogy - most come to it as a second career and have a pension income, redundancy payment or an understanding partner to help support them. Those that do make good money are often earning a significant portion of that from teaching, giving talks and writing.
I was told when I started out that it takes about seven years for your name to get known in the business - and that may be a little exaggerated but it does take a lot of time to build up a client base and a reputation - much work will come from recommendations and word of mouth so you need to stick at it.
Consider joining a professional body - you sound like a perfect candidate to join AGRA (
www.agra.org.uk) as an associate - which will then give you access to like minded people in exactly your position who you can meet with and discuss your business and also get work referred from other members or through the AGRA website.
I have reviewed business plans from numerous new researchers and never seen a monthly fee charging structure - but it is an innovative idea - but as pointed out by others you can only be earning pence per hour at the rate you are asking. I can assure you there are plenty of people out there willing to pay at least £20 per hour for good research work - and many researchers charge substantially more than that. Clients are paying for your time and expert knowledge but you also need to factor in all your costs - certificates, IT equipment, subscriptions, travelling, copying, printing, insurance etc. to work out what you should really be charging. And don't forget you pay tax on the income (profit) you make as well !
The growth and ease of internet based research means that not many people these days are willing to pay to "have their family tree done". There are still a few around but most clients who come to a professional are actually people who have done a fair amount of research themselves and have got stuck, or who want someone with specialist knowledge, or someone to visit an archive to look at original documents, the majority of which despite common belief are not available anywhere online. I also spend quite a lot of time unravelling existing research that has gone badly wrong (usually due to online research !) before I can even start to take things further back.
You need to know the holdings and workings of your local archives inside out and to see if there are any areas you can potentially specialise in - but don't take on work you are not qualified or competent to do. Many new researchers are quick to take on any project that comes their way even if it is way outside their expertise and knowledge which doesn't help them in the long run.
The Society of Genealogists also have a series of talks through the year loosely categorised as "Careers in Genealogy" and there is one next Saturday on becoming a professional genealogist which I found very useful when I started planning my business.
Good luck and please PM me if you need more advice.