Sorry even tho you said females only, I feel obliged to help.
Firstly, get contact lenses, no offence, but females who see a male with glasses instantly assume nerdy.
Secondly, hairstyle, man I really recommend a high number up top and low side cut, very stylish.
Use your 'skinny' physique to the best of your ability. Wear skinny jeans/chinos on nights out with casual tweed blazer and a nice shirt. Also you may wanna get some plain tees from topman, and get them in a small size like xs
Now you may think I'm mugging you off her, but personal hygiene is a big thing with females, that could be a reason, but they feel too embarrassed to say, make sure your shaven in the personal areas as they omit a lot of odour, and the deodorant that works best for me is sure, followed by some lynx
Other than that, it's fully personality mate, don't seem to eager, read signals and body language etc