My mantra for a while was "the floor is the biggest shelf in the room"...
Lack of space really does become a problem though; shelving really helps it.
One of my issues is boxes; boxes are a big waste of space, unless they are full, they waste so much space.
The same applies to other smaller containers on the workbench. You almost always go to fill the empty one because you want it kept separate, however this just wastes space.
I solved my problem by having a few small tubs/containers, and only a couple of boxes, every week i'd empty tubs/containers my stuff into ziplock bags and put it in the box, after a few months, i'd sort them all back into the component storage.
For bigger things that you can't really do that with, shelving helps a lot. Need room on your bench but you have 5 projects running and there is no space in between? Dump everything from the project into a ziplock bag, put it on the shelf.
The other big thing is test equipment and leads. You have to force yourself to pack up when you're done. Put your stuff away, tidy up your leads, put your drivers and cutters away. You don't lose nearly as much stuff that way and it keeps the space clear!