I am a fan of Gap jeans but you need to be sure of your size. I kept some of my gap long and leans and am glad I did as I will wear them again
I also like Levi's but they tend to have small pockets on the women's.
M&S have a really good selection, go in and try on lots of pairs . They vary from cheap and cheerful to posh ones, and have all sorts of styles
Fat Face jeans are pretty good too.
I'll wear most styles but am not keen on 'mom' jeans but will wear baggy dungarees Toora loora toora loo rye ay. At the time I refused to wear those low rise monstrosities that are now in the 50p tub at the charity shops. I get most of my clothes from charity shops and regularly find things like branded jeans (e.g. Levis) for £3 or less
I find 7 for all mankind comfortable
With jeans, go for a dark wash, and a straight leg, or a dark bootcut, and only wash them when absolutely necessary
Topshop is usually good for jeans, but I haven't any probably because I have so many gap ones
With jeans, buy ones with no or only a tiny bit of elastane, and wear a belt.