Is there really anybody there? Send them a question by email and see how long they take to respond. You want to know if they'll be there when you need them. Some offer 24-hour support and a few will respond quickly. Speedy customer service is rare and indicates a superior service. I think that this is the single most important consideration. Also, check out the quality of their online documentation.
2. Server performance
You want a server that is reliable and fast. There is a free tool available that allows you to evaluate this before making a decision! NetMechanic.com will measure the speed of access for all facets of access (network speed, DNS lookup, connect time, download time, and absence of timeouts). The "download time" statistic is the most important single item to compare. Collect your list of candidate hosting services and run side-by-side tests of all the candidates. Sample during peak and non-peak times for optimal comparison.
3. Are they familiar with the application you plan to use?
If you're planning to use a particular application that requires special setup parameters (such as Online Merchant, a popular online store), make sure your potential host is familiar with the application. Otherwise you may find yourself spending a great deal of time trying to figure out how to configure it - perhaps never succeeding!
4. Traffic allowance
Compare your traffic allowances. Some services give you a small limit on the amount of material that can be downloaded from your site each month and charge you large amounts when that limit is exceeded. Some offer huge traffic allowances (several thousand MB/month, where 1,000 MB = 1 GB) for the same price as others that limit you to a few hundred MB/month. Sure you probably need less than a hundred MB/month now, but why put yourself in a position where you have to move when your traffic takes off? Plan ahead and allow for growth.
How much space do you expect to eventually want for your web site? Planning ahead can save you lots of money later. If you expect to grow, look for a place that offers sites of 100 MB or more. Some services offer 500 MB sites for less money than others that offer only 30 MB.
Consider what features you want to simplify development of your web site.
Do you want access to a cgi-bin so that you can install your own scripts?
Do you want many scripts pre-installed and pre- configured?
Do you want to be able to use Microsoft's FrontPage?
Do you want autoresponders for email processing?
Do you want email aliases (automatic forwarding) so you don't need to check email in more than one place?
With so many hosting services to choose from, why not choose one that offers a guarantee? Services that offer a moneyback guarantee are confident that you'll be delighted with their service.
Look for hidden costs when comparing price.
Do they expect you to pay for a long term in advance to get a good price? Choose one that doesn't bait you with a low price that's only available if you make a long-term commitment. Will they handle the registration of your domain for free? If you're transferring an existing domain, will they submit the domain change to InterNIC for free?
Choosing an excellent service to host your web site doesn't have to require luck. Knowing what to look for makes selection simple.
Good luck with your marketing and God Bless
"How To Choose A Web Hosting Service" by Tracy Perrin of 500Megabytes.com