We've said it once and we'll say it a thousand times - physical appearance will never be the most important thing to a woman. So, when we refer to 'good grooming' we're not talking about being naturally 'hot' or anything like that. We're talking about when a man puts some effort into looking after himself. Some guys roll out of bed and leave the house, but it's honestly more attractive to women if you take a shower first.
And it doesn't end at showers. Wearing deodorant, ironing your shirts, keeping your shoes relatively shiny, and washing your hair from time to time also helps. Taking an interest in what you wear and buying clothes that suit your body type is another easy win. You don't have to be good looking, but some good grooming will always go a long way.