Re: What if your husband isn't attracted to you?
Not to be unkind, but what about his looks? Is he Mr. GQ Handsome? I understand a lot of attraction is physical, but it goes beyond physical - looks are transient.
But that being said, I always encourage dressing "well." I don't mean in super expensive clothes or the latest trends - but each person should know their body type and their personality and dress for impact. Dressing well is an instant pick-me-up - it gives a personal self-confidence and affects their posture and their socializing. When you know you look good (or well-put-together), it's one less thing to worry about and lets you focus on other aspects of interacting with others and socializing.
Skin - make sure your skin is well cared for and avoid foods that may cause acne. There are tons of threads here what to do for problem skin. You can use natural masks or store-bought products that can help you target problem skin. We'd need to know more to give advice on what skin issues you may have.
Hair - this is an easy way to "change" your appearance a bit and to give you a more current look. One of the keys though is to not look for a trendy cut, but one that suits your face shape and a style that's generally low maintenance.
Weight - that's up to you. If you think it would be good to lose weight, then do so. Change your diet, start working out. This requires a lot of discipline and the results will take time, but is probably the cheapest "make-over" option.
Clothes - it's really important to not buy something just because it's designer or trendy. What looks good on a size zero 17-year old is not right for a size-bigger 20-something year old. You don't have to dress "old and mature", but you have to be conscious of your body-type and dress to flatter it. What doesn't he like about your dressing sense and what does he think looks good? Mind you, his sense of fashion may not be fashionable - really, what does he know?
Make-up - there are tons and tons of make-up tutorials online. You need to figure out a casual, daily look and a fancy look. Practice it at home. You don't need expensive products, a lot of drugstore brands are pretty good and should be used especially is you're practicing.
The point I'm making is - you should want to look good for you AND your husband and there's no harm in updating your look. But don't adopt a look you're not comfortable with and he needs to also realize he's got a crappy attitude if he's making you feel bad about your appearance.