1. If they say that they offer 'unlimited' databases, be sure to ask them if they limit the no. of database queries on per hour basis.
2. Make sure your webhost has the latest server softwares running, especially if you need to use server side scripts such as PHP-MySQL, PERL, etc. I remember developing a site on my local machine where I used XAMPP as server and when I uploaded the site to the webhost, it didn't work at all. Reason: Because XAMPP used the latest version available then (PHP 5, MySQL 5) whereas my webhost was using PHP 4.4.7 and MySQL 4. That was a jitter to our web application. We changed host without wasing time. And it worked.
3. Check that other sites hosted with the webhost are 'clean'. You can do that easily with *www.myipneighbors.com. This is especially important when you are buying shared hosting. Some email providers are known to use a blacklist of IP adresses which belong to spammers. If such a spammer site is on the same server as yours is, all emails from your website to the people using that email service will be blocked as your site shared the same IP address. To check if your shared IP address is blocked, just ask the host to give you a free subdomain for about an hour and send test emails to your email accounts on those sevices. If you receive the email, congratulations, else ask if your webhost gives a dedicated IP address (for a small extra fee). Again send test emails anf check. In nothing works, choose another webhost.
4. Don't fall for the 'cheapest' web hosting. If you cannot afford an expensive webhost, go for one which is not the cheapest but one or two positions away from the cheapest. 'Cheapest' are vulnerable to abuse by spammers resulting in blacklisting of IP adressess of the server.
5. This is a must if you have a 'Send this page to a friend' facility on your webpage. Make sure to use CAPTCHA.
If you do not use CAPTCHA, automated visitors(bots) will abuse your script and send spam resulting in your domain/IP address/both being blacklisted by users/email service providers. CAPTHCA reuires PHP and MYSQL so make sure your host provides it.
6. If the webhost has a support forum, just hand hang out for few days in their forum and obnserve what discussions are going on, whose having what problems and how fast is the company answering them. If you feel, you can go a step ahead and privately messsage few active users from their forum for a feedback.
7. While comparing two or more webhosts, don't compare on points such as web space and monthly bandwidth. I have observed webhosts giving 150 Gb diskspace but frankly, I am not sure how many would use even 50 MB.
