I'm polished but not glamorous and I think a lot of it comes from within. If you put weight on you can still buy nice clothes you don't have to wear leggings and t-shirts. I know fat people who are groomed and some are glamorous.
I agree with pp who say look after your hair, nails, skin and teeth and iron your clothes. Choose clothes that suit you and good underwear and shoes, hold your head up and you instantly look more confident. Going to the gym makes me feel better but doesn't add to looking groomed.
I have my hair cut and coloured in a salon and visit a dentist for my teeth but nails, face, skin I do myself. I think it does take time to be groomed though, I don't get people who say a few minutes a day, it takes at least 2 minutes just to clean your teeth, a few minutes to me is less than 10.
I shower, cleanse my face, brush my teeth, wash my hair, blow dry it and moisturise my skin that's basic morning routine and it takes more like 30 mins. I would say my own pedicure, manicure and facial take me at least an hour including getting all the stuff out and tidying up.
I always use gloves for housework and I often moisturise my hands, arms and legs during the day. Every other day I put a clear top coat on my nails to make them last a week. Hair removal, eyebrows or any other extras add time and I don't have Botox, fillers or anything else that adds extra time.
I do think about what I wear, in that I always coordinate my outfits I can mix and match but some things I will never mix. This is probably why I have more footwear and bags than one woman should ever need.
Some people look polished and glamorous with little effort I think if they have good hair and bone structure it helps. I have to work at it. My DP looks well groomed when he leaves for work every morning and by the time he comes home he looks like he's fought his way out of a hedge.