The instant google moved from a text based spider to one based on Mozilla, it became crucial to test the site in firefox. Most designers however ignore firefox as they say that not many people use it. If NO-ONE used it other than google then it is crucial, given that googlebot by default accounts for 80%+ of the traffic in the uk.
I don't really design any longer, but I would reccommend designing for firefox as any IE problems will be well documented online and therefore easier to fix.
By the way, I forgot to welcome you

Welcome to UKWM, stick around as we have some decent people on here and it will help you with regard that 'all alone' feeling.
AS an aside, I had a client who sold baby gifts. Sadly because of family issues and the runaway success of their other business, they closed the shop in August last year. They have slipped from the first page, but are still on page 2 of google for the phrase baby gifts
I have to say that it was a fairly difficult area to work in, but once you get there it is great.