One of the ealier post mentioned
SEO.
I would say that first before you go ahead and start selling and heaviliy marketing your service you need to get your house in order.
What i mean is make sure thay your site is up to it and that you have no bugs and glitches that a potential customer might feel discouraged by.
Make sure your site looks good and is apealing to the target market.
Make sure that all you site is easily accessable and that you have a simple sure way of locating your products. have someone that knows what they are doing to copywrite the content so that you hit an average 3-5% of your keywords within the body of the text. you also want the test to be clear and as descriptive as possible, but not long winded.
Optimise your
SEO by selecting appropriate keywords for your metatags. Remember, you might want to use the adwords tool to help you select these.
Post in forums such as these and create accounts on all the major social networking sites. Make sure that you alway submit links everyehere and in every signature containing your url. Post, post, post post..... etc....
Register the business in the directiory services (hotfrog etc...) you name it.
My personal favorite is make a Viral Video and post it on youtube which will include advertising for the site. This is a awesome way tio get hits.
The objective of the game is to get your name out there as much as possible.
Print, TV, Radio - they are all good but your target market is allready online so you dont need to tap into that. Research, research....etc...
There is so much out there. There is no one thing that will give you success... it's going to be hard work and sleepless nights.