Dedicated server offers more functionality and power in comparison with shared hosting, but before you switch to it you have to consider some things. All hosting companies are different and don't try to choose much cheaper server - you could end up with bad one.
So how not to make mistakes and what to pay attention to?
Because of the fact that you rent the dedicated server physically it is very important to pay only for quality hardware and not for the old and outdated one. That's why search the hardware with hard drives of corporate level or even SSD. Try to choose some brand, such as Dell or Supermicro. Those servers are usually of good quality.
Every hosting company offers this or that level of support, but that's what you have to take into account:
1) What happens if there are problems - is it easy to reach the support?
2) Does the company have full time support?
3) What is the response time?
4) Can they really solve problems?
Hardware replacement guarantee
Usually when you have problems with server hardware your hosting provider or data center offers to replace failed hardware in some time. Usually, the cheaper is the service, the more time they take to replace hardware.
- operating system
Learn if your hosting company offers all main distributions of Windows and Linux. If they offer only Linux, it is likely they won't be able to answer the questions on Windows.
- control panel
Mind how the control over the dedicated server is implemented. The provider may have its own control panel but you should be free to choose from well-known solutions, such as WebHost Manager, cPanel or Plesk.
Network quality and uptime
Even if you take server of good level and your data-center is situated on a good location, it may not be enough - you should also take uptime and network quality questions into account. Pay attention to those companies that are good at it.