If you are considering switching web host providers there are 5 things you should consider:
1. Back up your files! In fact, back them up two different ways, just in case one gets lost or fails for some reason. Most web hosting companies allow free transfers or discounts on transfers.
2. Contact your customers or friends. Notify your customers or friends well in advance of the changes you are making and the exact dates they can expect the changes.
3. Keep old account for a while. This may only be a week or two but you do not want release any of your files or space, or burn your bridge with your old web hosting company until you are completely sure you were able to transfer all the files from your old website and everything is up and running as it should be.
4. Test the new site. Many web hosting companies are willing to work with you and allow you to test your new site live prior to shutting down your old web site.
5. Double test the new site. Now that you have your web site fully transferred up and running check all of the links, scripts, databases, and email functions to make sure they are all working. These files can usually be fixed fairly easy, just need to check them all so nothing gets overlooked prior to your friends, family, or customers try to access them.
Remember to always read web hosting reviews and do comparisons with several different companies prior to choosing one so you can rest assured that your web hosting company will offer you everything you are looking for.
Hope this helps you in your transfer.