Ah congrats!
As PP said, what equipment does your company provide? Do you need extra monitors? I find a properly adjustable chair with good lumbar support invaluable (expensive, but worth it to sit on for 8+ hours a day!), a good footrest for posture under the desk and a laptop / screen raiser too. A good mouse mat (with a wrist support!) and keyboard support also really helped I found.
I'm a sucker for organising, so I have pen pots and desk tidies to keep my space clear. I use the cable tidy wire hiders to keep the cables in control and command strips to run these around the underside of my desk so there's no trailing wires.
Make sure you have a workspace that is clear and clutter free, get everything you need in easy access (pens / paper / notepads / headphones for calls etc) and try to make sure you're in a distraction free area. Give yourself hard stop times in your day, take five minutes to get a cup of tea or drink, walk about a bit and get your eyes away from the screen - you'd do this in a regular office, so do it at home! If you can try to be near natural light, it's a definite mood improver.
Don't chain yourself to your desk - make sure you take your allotted breaks and try to get out of the house every day. A good internet connection is a must!
Find out if you're allowed to work outside of the house (sadly I'm not!) but a coffee shop morning each week can break up your routine. Make scheduled time to catch up with Co workers, we have weekly team meetings just to grab a coffee and chat on video Skype - helps keep a good team environment for us!
I'm sure there's much more, but this is what I think of immediately 😊