Box all the stuff up that you don't absolutely need. Take out more than you think you need to. You'll have to pack it up to move, anyway, so why not do it now? If you can afford a storage unit that's close, get one to store extra furniture and all those boxes, so no one even sees them in the garage. But since you're just moving down the street, that may mean too much extra work.
Try to just keep enough furniture in each room to give it a "purpose." If it's a bedroom, only leave a bed, a dresser OR nightstand, and a small chair (if there's one in there already). If it's a living room, leave enough seating that you could have a comfortable conversation, and end table or two, and a bookshelf or two. You don't want anyone to walk in and wonder what they would do with that room that's totally empty.
Also, when you're deciding what to box up, take out anything that doesn't look new and shiny, or that doesn't quite coordinate with the rest of the room. Only leave out the best of the best. The prettiest books that harmonize color-wise, the furniture that shows the least wear, etc. If it looks at all shabby, pack it up!
If you have a dining room table, set it, or artfully set out stacks of dishes, cloth napkins with rings, fancy glasses, etc as if you were about to get ready for a fabulous dinner party at a moment's notice.
If you can, buy new, fluffy towels and hang them in the bathrooms. But don't use them! keep yours under the sink for a while or something.
I did most of those things and we sold our house in a bad market, in a not-so-great part of town (it was in decline, which is one reason why we left) in just 3 months! We had lots and lots of Realtors tell our Realtor that our house was in their top 2 or 3, too.
And don't rely on the Realtor to take great pictures. Go ahead and take pictures of your rooms as you get them done. Try different angles. I even got a step stool and stood high in the very corner of a room, smashing myself up against the wall. It's amazing how much bigger the room looks. If the Realtor wants to take more pictures, let him/her, but yours may very well look better!
Oh, and when you take the pictures, turn on lamps, etc. for warm lighting.