Oh Oh Oh ...pick me , pick me..
just my idea..
pick the colors that you like , 3 will be fine , make sure they go together, and they will also feel cozy and warm in the winter , ...then get all your horsey things that are important to you...pictures , horse shoe of your horse, maybe an old bridal etc..with the pictures , have some blown up , so you have different sizes, then frame them is frames that are all the same color ( or near about) bit differnt sizes, maybe some metal frames too, but all dark or light . arrange them on the floor ..maybe you want them going across the wall behind your bed, or grouped over your dresser , You can pick up an IKEA catalog to get ideas on how to arrange picture frames, then make another grouping for another wall,of a horse shoe ( we all could use a little luck) and your old bridal, maybe a nice leather crop ( make sure people dont get the wrong idea on the whip in the bedroom) Ask your ferrier to make a cool hoof pick out of an old iron shoe, alot of them like to do that kind of stuff. just group these things together. So there are 2 wall groups in horse themes...then something I have always wanted to do was make a nice sattle stand painted , one of the colore you have picked for your room . you can use a sawhorse,cut it in half to shorten it then put it back together so it is tall but not so long , then shine up a western or english sattle that is used, and there is a douvet rack, for your bedspread. You will have to modify it so that its not so long , you can get the two leg pieces that clip onto the wood , and cut the wood so its only about 2 feel long, so the sattle fits just right, without wood showing on either end. If you want to paint walls, I suggest painting 3 walls one color , the lightest color , and the third wall the darker color. The rest is up to you , but that is a good foundation.
good luck