What can I do without a lot of closet space?

Fix What?

KonMari method. Only keep what sparks joy and use her folding techniques for the rest.

If you haven't worn it for a year, donate it. Double up your rods, one high one low. Visit closet showrooms for ideas.

You could zip tie inexpensive plastic crates on top of your top closet shelf in a row. The crates would provide another layer of storage in your closet. These DIY storage ideas might help, too: https://www.goodhousekeeping.com/home/organizing/g2171/diy-closet-organizers/

I did a full closet makeover on my blog with my friend who's a pro organizer. Our closets may not be the same size, but it may be helpful to give you ideas! https://rootsandwingsfurniture.com/blog/diy-closet-makeover-part-1/

Double your hanging space by using inexpensive key rings you can find by the bag in most craft departments, there are several things you can put over your hanger stem to double your hanging space.