Disk Space and Bandwidth
Bandwidth will basically determine the level of traffic your website can handle. Each web hosting package will have its own bandwidth limitations and restrictions so you will need to ensure you have enough bandwidth for current levels of site traffic and also some extra in case your website takes off in the future.
Disk space is basically the amount of storage space assigned to your web hosting package. This will also be restricted depending on the web hosting service you have subscribed too. If your website has a lot of graphics and social media options then you will need a lot more space than a simple text content based website. Make sure you have enough disk space for your needs and also room for any future developments.
One of the most popular operating systems for web hosting is Unix (Linux, BSD etc), as this provides flexible programming and scripting options such as PHP, FrontPage and Perl. Unix based operating systems only have limited ASP functionality (Microsoft based product) so if you are running this type of application you would be advised to choose a Windows hosting plan instead of a Linux hosting plan. These will also offer PHP, Perl and MySQL.
Uptime and Downtime
Uptime figures for web hosting services are a very important consideration for webmasters, especially for those running online businesses. It basically means the amount of time your website will be up and running and downtime is when your customers and visitors will be unable to access your website.
Downtime can occur for a number of reasons such as essential server maintenance or even overloaded servers. For the best deal you should be looking for web hosts that are offering at least a guaranteed 99.9% uptime. This is realistically as good as you can get at reasonable costs and any downtime will be such a short length of time you would probably never even notice it.