Improvements to a magento site

Hi, I have a new site in magento.
It hasn't been done properly so I need some help.
Specifically I need:
to sort out the urls (they change as you explore the site)
set up the shipping
set up paypal properly (have longstanding account)
improvements to the checkout/basket
put a signup to newsletter box in place.
putting in a gift-wrapping option
linking to Facebook and twitter accounts


plus I need a lesson in:
changed the images in the carousel
fixing the image sizes in each product page
setting up related products

Thanks in advance