Physical attractiveness boils down to whether someone looks as if they would be a good 'vehicle' in which to pass on your genes to the next generation in men, height, clarity of eyes and skin, muscle mass and tone, good teeth, and other 'health markers'. This all adds to a sense of health, vitality, and a good genetic bet.
In both sexes, physical symmetry is deemed most attractive. However, someone can look great, tick all the gene boxes, but leave you colder than a March morning on the north face of Everest. Attractive people can even be 'ugly' on paper, but they hold some kind of fascination.
What I want to talk about here are the behaviours that will make you more attractive regardless of how you look.
you'll see hundreds of young men and women all dressed the same, same clothes, speaking in the same tones, using the same words, texting furiously at the expense of just enjoying being with the people that are physically present. Of course, conforming to type is important for most young'uns - especially if they feel they haven't yet formed their own identity. But to be especially attractive (above and beyond physical looks), you need to be a little different or at least memorable.
Consider adopting a certain subtle style of dress. Decide what your opinions are. Don't just go with the herd. Listen to and learn from those who communicate well and learn to communicate in your way.
So you may not naturally be the most symmetrical, or handsome man, but anyone can try to get enough sleep and exercise (both of which are natural beautifiers), eat healthily, and avoid too much alcohol.
If you want to be more attractive, don't communicate too much negativity. Cynicism is depressing. But it's especially not a great idea to rubbish your ex-partners (at least not too soon!).
Hours spent offloading your regrets, anguish, and resentments over past loves can make any possible new ones feel as redundant as sunscreen oil on a winter's midnight. And they may feel they're getting an unwelcome glimpse of their own possible relationship fate.
The need to feel protected apparently runs deep. But it also seems that some gays don't just like macho, but a blend of brave and caring, tough and sensitive. Demonstrating these traits is what makes you attractive - so if you're a guy, cuddling a poodle whilst talking about your next white water rafting expedition should do it.
Remember, all of the above should be by products of you relaxing with yourself and being friendly and interested (which make you interesting). Trying too hard to 'be more attractive' can produce diminishing returns as the 'trying' starts to get in the way of the 'just being'.