Beyond that there are a few things that enhance the process and just make for a better creative experience. In my case, the outside has as much to do with it as the inside. I love the happy colors that I had my daughter paint on the outside. The yellow, green and purple greet me with a feeling of perpetual spring, even when we are buried in snow.
My studio is basically a 12 x 20' Amish shed that came to us bare-bones and unfinished studs on the inside. My husband and I finished it with drywall,insulation, flooring etc. We made the ceiling Cathedral which gives the small space a feeling of having more room than it actually does.We added track lighting to shift around the room to light paintings on the wall and I ordered extra windows in the back and large rounded windows on the doors. My window boxes were an essential for me. The flowers that I add them to each spring add a homey touch and contribute to the happy feeling of the exterior.
Inside, some of my must-haves are my little portable speaker which hooks up to my iPhone and plays my music as loud or as quietly as I am in the mood for. This replaces my iHome which stopped supporting my iPhone about two generations ago.
I also have my cute little red IKEA couch for those times when I just need a break or a place to sit and gestate ideas or a home base to wrap and write up orders during open studio.
My coffee pot is essential. I guess I shouldn't called it a pot anymore now that we have Keuregs. We used to be very anti-Keureg in this family because of the waste of all the little k-cups but my husband relented last Christmas and got me a small one for my studio. I have to say that I absolutely love it and the coffee that it makes is just the best. Aside from McDonald's, I don't think there's anywhere that I get it as piping hot. I keep a small refrigerator in my studio though I'm not sure that it's an essential except for during open studio when I put cheeses and fruit in there to keep from one day to the next. I do also keep some cold beverages like seltzer and beer and soda for studio visitors.
My two other essentials, or maybe I should say three, are my window air conditioner which I absolutely cannot be without in the summer and in the winter I am kept warm with two electric space heaters.
It depends on the temperature whether I need to run both heaters or not, but this winter, given our many days of temperatures below freezing, I had to keep them both running 24/7 to prevent my clay from freezing and rendering it all unusable.
I bought a handy little thermometer which keeps me apprised of such things and therefore is an indispensable studio item. My little wooden figure which stands next to the thermometer, is sometimes helpful when painting people, but he doesn't bend too much so he just hangs around a lot to remind me that I am indeed and artist.
My little "create" sign, a gift from my daughter, serves a similar function, reminding me to get going and do what God intended for me.
Lastly, is what I call my "wall of validation". On it hangs ribbons and plaques that I was awarded over the years from various art shows. I keep it there to look at when I am stuck for ideas, when something isn't going right and I am convincing myself that I stink as an artist, or during those lonely times of creating in my solitary space, it reminds me that someone thinks that what I do is OK and maybe I should just keep going :0)