I am excellent at organization. I look at the like items example: dress up clothing, and put them together. so then I see what types of storage I have for these different sized items. I use things like the larger size freezer storage ziploc bags(, make sure they have the plastic zipper, they last longer and are easier for kids to open)I tend to use things like zippered plastic bags that sheet sets come in, those are the best! If you go to IKEA.com honestly not a plug) I purchased some fanfreakintastic storage units there, a staircase style in white with trofast storage trays. one set of shallow in free, a deeper medium in pink and red, then one very deep one in blue. I also purchased a 3 storage drawer box that i use for all the little things that don't go to anything ex: mc donalds toys. works perfect, holds a ton, and it doesn't look messy! oh oh! I also purchased one other box that I really like, very handy are these colored bins made of collapsable walls from target they are 5 dollars each and measure about1 cubic foot. they are made of cloth with I think cardboard inside the walls and the bottom you take out to collapse it down to 1/2 thick.
I say this with you understanding that I have 3 girls worth of toys and clothes in one bedroom and it doesn't look cluttered. all with the help of the items above. :) I really hope that helps!