I've worked at home since 2003 when I became UK employee #1 of a US company (ironically, over the last year, after a role change I've started to go back into the office, but only two days a week). It's an adjustment.
Have an 'office', if you're lucky as me, an actual office, if not sequester a defined area of your house for work. Make it abundantly clear to other family members that just because you are home, it doesn't mean you can do the laundry. Have a schedule, it's perilously easy to start a bit early and find yourself 'just finishing up something' at 9pm. Every day. Have a start and finish time. Break up your day, go do some exercise, get lunch etc. Make sure your employer have you set up with all the newfangled IT tools.