This is a very difficult, and quite expensive task to take on. A good way would be to become a contributing member of numerous forum communities that are focused on niche markets that revolve around the need or discussion of web hosting, from there you can generate posts within said marketplaces. There are so many hosting providers out there, you need to establish why a customer should choose to go with your company rather than a company such as HostGator.
Unless you've got a hundred thousand in the bank for marketing, don't expect to get big in a short period of time. And most of all, don't quit when you think the going is tough. It took nearly 4 months before we started gaining customers, and now we grow every day. It's a tough market, but it is one that I believe in and have been involved in since a young age. Be sure that before you jump in that you've got the experience and money to do so.
I would create an affiliate program for the hosting company then attract a lot of affiliates to promote it. One other thing I would do is to find popular forums and blogs in different niches.
Offer them 6 months of free hosting in exchange for a review (blog post, forum sticky post or even an email blast) also encourage them to use an affiliate link in the reviews and share the affiliate link in their social profiles once in a while to increase sales.
I would go to an ad network like BSA and investigate some sites there to advertise on. Web hosting does great on webmaster forums, if you have a great deal and some incentive.
I've sold SEO services advertising on BSA and wish I had continued. Here's a gem because I've kinda veered away from reselling cheap SEO services on the web.
On BSA I found a site called Small Seo Tools. My conversion rate was through the roof. Just in 10% affiliate sales, I made $400. Thats $4,000 in sales! Not to mention the aff commission was mostly from my services on SEOclerks so I was making $$ on the services I was selling as well. Probably saw a few thousand in profits off of a $225 investment.
I should have continued but became to busy and the tedious micro gig work wasn't doing it for me. So I didn't renew my ad.
Had I thought for a minute, I would have hired a VA. Yes I am kicking myself now.
Anyway, I know this site converts but the freaking waiting list is almost impossible to get through. IMHO advertising is the way, if you know what you're doing.
Put a banner up here on Webmaster Sun and see how you do. Our rates are better then anyone on the web and we do rank on the first page of Google for keywords that get tons of searches. You'll get plenty impressions and if you use a shortened URL you can track clicks.
See the ads to the right >>>>>>>>>>>>>>>>>> and up ^^^^^^^^^^^^^
It's important to keep in mind that web hosting is not a get-rich-quick scheme. It can take years before you see actual sustainable profit, and certainly before the investments you made are returned.
For us, staying active on social media (including forums like WMS) has been going great. Apart from that, we've published a few videos to help increase conversion rates - and on top of that, word of mouth does quite a lot.
Adwords can be extremely effective if done right - but can also be the death of a small business, as the rate for good keywords is rather high in most areas. Staying competitive on those keywords in the US & Canada for example will put you at between $50-$100/day in advertising. If you have a large budget for it, that's a good way - conversions are usually in the 5%'s.