A full size bed, the kind you still find in guest rooms and older houses with smaller bedrooms, measures fifty four by seventy five inches, which sounds almost the same as a queen until you put sheets on one and realize how much narrower that really is. Good full bedding fits that frame without swimming on it or pulling tight at the corners every time someone rolls over, and it should feel substantial in your hands before it ever touches the mattress, the kind of weight that tells you the cotton or the linen isn't cutting corners to hit a price.
If you're starting from nothing, I'd buy the sheet set first and worry about the rest after. A plain white or cream percale in full size, nothing printed, nothing with a pattern you'll tire of in a year. That gives you a base you can build on with a quilt or a duvet later, and it means the bed looks finished even on the nights you haven't gotten around to doing anything fancy with it. Pattern and color are the fun part, but they're also the part you'll want to change your mind about, so don't spend your good money there first.
In an ordinary room, full bedding sits well with a smaller frame, something low and simple, because the size of the mattress already does a lot of the visual work and you don't want a headboard fighting it for attention. It pairs easily with a narrow dresser or a single nightstand rather than two, since a full bed rarely has the floor space on both sides that a queen does. Keep the rug plain if the quilt has any pattern to it, and leave at least a couple of feet of walking room on each side, because a full bed in a small room can crowd out everything else if you let it.
This size makes the most sense in guest rooms, smaller bedrooms in older houses, studio apartments where one bed has to do a lot of jobs, and homes with kids who've outgrown a twin but don't need a queen yet. It works in any season, though I'll say heavier bedding shows its size more in winter, when you're layering a quilt over the sheets and the whole stack needs to still fit the mattress without hanging off the sides like an afterthought.
The first thing to check is the stated fit, full versus queen, because the two get mislabeled more often than you'd expect and a few inches off makes the whole bed look wrong.