trademe/buy sell selling tips

I have three gorgeous kids and a whole heap of their clothes to sell, toy, baby stuff etc. Im not getting anywhere in selling it. I have sold a couple items on buy sell but nothing else. On trademe I have them in bulk lots and still no-one wants to bid. On the buy sell pages I've joined heaps but not single one seem to want to buy. No idea what Im doing wrong and would love some tips please