By getting a domain name you have an address but for existence you need to buy some space to host your website.
According to your site's characterstics you have to select the web hosting plan.
The main factors we have to consider are
a) Plan fee=>The amount we have to pay for a plan(monthly or yearly)
b) Disk Space=>The total space(GB) to host our site
c) Monthly traffic => The total bandwidth allowed for site( if our site needs file upload and download functionality, then we need more bandwith )
d) Addon domains => If we need to host more than one site, consider this.
e) Developer tools => The tools needed to develop a site like php,asp,jsp,python,perl etc
f) Company => The quality of technical support of web hosting company
I will recommend Web Hosting Plans Monitor for selecting a suitable web hosting plan.