One thing I would add to all this is that you should be looking for quality garments. Make sure your knitwear is non-man made fibres, T-shirts are 100% cotton etc etc.
To get your head around what colours you like together, look at the street style and lookbooks sections on here. While the looks may be a bit outlandish, the colour principles remain the same.
In Bristol you should be looking in Reiss, All Saints, Kurt Geiger, Garment Quartier, House of Fraser, French Connection. I also love a bit of TK Maxx, but if you hate shopping it will probabky be your idea of a nightmare.