Hello Junaid,
there are a lot of factors you need to consider while selecting a web hosting company for your website if you are serious about your website. The importance of having a good web host is that - on a long run there are many factors that could hinder your website growth.
1. make sure you go for a reputed brand to ensure continued service
2. check online for reviews that would give you more insight on web hosts
3. pricing is important factor for any startups - so go for hosts offering reasonable prices
4. make sure they have the latest versions / technologies like PHP5, apache etc.
5. decide which OS to go for - linux or windows
6. learn about their data centers and their locations (geo based traffic / targetting)
7. analyze your website requirements - bandwidth / DB / space
if you want to know more about best web hosting companies - you could check out a detailed review
here
hope this information was helpful.
cheers
Josh