HGTV - you can get some ideas from it. But - a lot of stuff I watch there makes my hair stand on end and shows me what not to do.
I have benefitted from shows about staging, that seems to be a science of it's own. I do believe it does influence sales price disproportionately, a lot of people buy on the basis of their feelings and not their brain. So, staging can give you a huge advantage for little effort. Long as you know what you are doing.
There is a spacial aspect - correct placement of the correctly sized furniture can increase the perceived amount of space and at the same time make the place look warm.