We're visual creatures living in an increasingly visual world. How you present yourself matters, but it doesn't all matter equally and men often spend time on the lower priority, more expensive areas before handling the basics. In decreasing order of importance:
I am continually shocked by how many people fail at this, especially since it's basically just pass fail and the results come from basic inputs.
That's basically it for grooming. The bar is under the floor. Don't smell (including breath), cut your nails and hair regularly.
I've already covered this in baseline fitness standards. They were originally developed to capture the health benefits of working out long term, but our perceptions of fitness are intimately intertwined with actual health.
The standards recapped:
The sleep (looking tired never looks good) and the proportions are of particular importance here, but they all work together synergistically. Might as well move well and feel good in addition to looking good.
Certainly you can take it even further. Achieving the following proportions will get you steroid accusations, but the originals above are more than sufficient.
Bodybuilding side-quest:
TL;DR: read The Appearance of Power.
Once your body is groomed and in decent shape, the next most important aspect of your appearance is how you dress. You're always wearing something around other people, with very few exceptions. Clothing expresses tribal allegiance, taste, indicates values and desired activities, and most importantly, for men, it conveys power.
Most men dismiss fashion because they see women's fashion and it doesn't appeal to them. Women's fashion is focused on beauty, and tribal belonging involves keeping up with an endless series of trends. But men are not women, and men's fashion is very different. While there are trends, they are entirely optional (as long as you don't want to communicate that you're "trendy" with your clothing). I spent far too long trying to run away from fashion and style. But now I use it to program my own feelings about myself, which makes me act differently, makes other people perceive me differently, and allows me to shape the world around me, all for a few hundred dollars.
Tanner goes into this in far more detail and far more eloquently in The Appearance of Power. Read it, its only 100 pages and I promise its worth it.
This is everything else: your car, house, office etc. These things all effect how people perceive you, but on a per dollar and per unit of effort basis, the previous three categories are much higher ROI. Certainly there is a lot of fun to be had here, and at the highest levels this becomes about crafting a life and a territory in which to live that life that is completely in alignment with your internal self. But make sure you have the other three areas handled beforehand. Too many fat men trying to make up for it with a boat.