Preparation:This is the most important part of your switch to Linux. Rushing through this part is a very bad idea, so please don't do it.
Identify your needs
What software do you need to run on a day to day basis?
What does each machine in your company need to be able to do?
Explore cross platform software
Before switching, check out cross platform software that has a Windows and a Linux version. Firefox, Google Chrome, LibreOffice, etc. all has versions for both platforms. If you are familiar with the software you will end up using the transition will be a lot easier.
Start checking if your hardware & peripherals are Linux compatible
Most computers and laptops are Linux compatible, but it is still a good idea to find out before you start.
Also a lot of peripherals are simply not Linux compatible. I have a Canon Lide 90 scanner which works on Windows XP, VISTA and 7; but refuses to work on Linux or even Windows 8. What am I saying? Updating your operating system will not guarantee that all your devices will play nicely.
If your printers, plotters, scanners, etc. are not Linux compatible - can you afford to replace everything?
What is the easiest and most reliable way to know if my peripherals are compatible?
Burn yourself a Live CD and boot up Linux, without installing it you are still able to test it. This way you know for sure that your hardware is or is not compatible. It is not difficult to do.
http://unetbootin.sourceforge.net/ and download Unetbootin for your software platform
2. Go to the Peppermint OS web site and download the 32 bit / 64 bit version (if you are a Windows user, right click on My Computer, then left click on Properties. The version of Windows you are running should mention 32 or 64 bit)
3. Run Unetbootin that you downloaded, Click the button with the 3 dots (bottom right) then locate the Peppermint ISO you downloaded in step 2, double click it
4. Plug in a flash drive (warning, it will format the flash drive so use one that does not contain important files)
5. Click on Drive (bottom center) and select the flash drive
7. Press F2 or Del (depending on your computer) and select Boot from Flash drive, in the boot settings menu.
8. Save and reboot
9. Select Try Peppermint OS when your computer starts up, if you select Install it will install Peppermint (either alongside Windows or erase your hard drive, depending on your choices)
When you shut down, unplug the flash drive and when you boot up again you will be in Windows again,
This is only a very basic tutorial, This will let you try Linux before installing, you can connect your peripherals and try to install them (if you have problems with that, please ask the friendly folks in the Peppermint forum, as they are much smarter than me).