GIlly, welcome to the e-commerce world.
ok... I took a look at your site. Would i be right in saying you made this yourself?
I'm going to give you some quick tips, that will really help you. I am father of two boys and I think your idea is good, swapping/selling clothes, but remember you are potentially competing with the likes of eBay, buy and sell etc for selling clothes, so you will really have to make your business message clear and emphasis the benefits of your website. I'd even suggest changing title of your website... e.g. call it something that really gets across what the site is about - e.g. babygearexchange.com or something..
You need to be laser focused on what your site is about to guide people through sales process. It needs to be a lean website. as users are task orientated and you need to make it easy for them to preform the tasks and have no content that doesn't truely benefit your website.
- puzzles, find a home - got to go.. not what they're on your site for, keep people focused on your core business.
- about us needed, and contact address - adds a reliability/confidence factor
- If you have a few hundred pounds to spare, get a professional graphic web designer to give key pages a revamp, and more professional look. It will ulitmately benefit you overall in terms of more advertisers and user who feel confident in using your website.
- You can still keep all those relvant third party links/adverts but there are some industry standard sizes which may help make the banners look better. And if you get other advertisers on board in future, they will most likely be able to provide you banners in size that will fit your pages. Check out iab.com , ad sizes are there.
- You need to make the shopping section more prominent if this is the area that is the core of the website. featured products on homepage, add the main categories as navigation items on homepage, and on left hand side. Keep all image thumbnails the same size - will make the page look tidier and more professional. ensure when you click into a product you have the product image and details on the product to reassure someone that they should buy it.
I hope these few things help... u will then need to work on getting your traffic numbers up.. thats a whole other post!!