I sell heaps of baby clothes on e-bay, I make sure everything is washed and ironed and take really nice pictures in good outdoor light.
I find this makes a huge difference, I still don't always make that much per item, but it all adds up, a lot of the time e-bay is alot of effort for a small return, we don't have much cash so it is my 'pocket money' to buy frivolous stuff, so I find it worthwhile and I enjoy it too tbh.
For clothes you really need to start stuff at 99p or less, and accept that quite a bit will sell at that price. If you can't bear to let it go for less then start it at a higher price, but it does seem to put lots of people off. I think people bid on it thinking 'bargain' and then get determined to have their 'bargain' despite the fact the price is getting higher and higher iyswim.
Don't put anything worth any money on until you have a good feedback score as people won't pay as much from someone who hasn't sold much.
Clothes don't often sell well out of season, so now is the time to be listing autumn/winter stuff, save any summery bits until next year.
Oh and it is realy quiet atm as lots of people are on holiday, wait until September to start and use this time to photograph weigh and catalogue everything.
Hth