One thing I notice a lot these days is why nice guys are the worst debate. The reason for this is I can see a lot of this being misconstrued and loads of genuine, accepting guys changing their ways and becoming A-holes due to the fact that they think this is going to get them places.
1. Being a nice guy doesn't entitle you to any girl! This doesn't mean that being a douche entitles you to any girl either. For guys that don't have beautiful faces, tons of money and an underwear model's body you have to put something else on the table. Being a nice, caring person is a strength but not a deal sealer. Add other traits to your palette. What do a lot of girls like? Confidence, sense of humor, your own opinion - the list goes on and on! Generally the key to being desirable as a male is to love yourself. This doesn't mean take 30 selfies a day with no shirt on, but take pride in yourself.
2. Be nice, but not too nice! I lost the girl of my dreams due to this! Ignore all the alpha:beta BS because it's just a social segregation. But when a girl comes into your life that you spark with don't chase her out the door. We go back to the guys greatest asset, strength! Sometimes relationships just work, I am envious of these people, but for others it isn't that easy. A girl can seem completely into you for a month and then vanish in a puff of smoke. The big mistake here is to beg for her. There's always a reason for this. Maybe an ex boyfriend has heard about her dating and came back, maybe she's caught up in some other life problem, or maybe she realised she isn't that interested in you. In these situations you cut contact, you're still being a nice guy by giving her space or letting it end peacefully, but you aren't presenting yourself as a doormat. Some girls will just be flat out honest (If you could all be like that that would be great at times) but some might like having you hanging about as a fall back and some might just like all the friendly attention you give them when douce bag A, B or C sleeps with them and doesn't call back! See the pattern here. This doesn't mean be like douce bag A, B or C but have self respect, You aren't someone's silver medal.
3. Finally guys don't pursue girls because you are nice! Let girls pursue you because you are interesting. Yes you might be short, yes you might be going bald at 21, yes you might be blessed with a less perfect smile. Don't let these traits drag you down however. Everyone can improve their appearance. When I was 20 I weighed 11 stone and had no muscle tone whatsoever, I had really bad spots and slightly bucked teeth. 3 years later I've noticed a lot more female attention and can at least kiss a girl every time I go on a night out. What changed? I got some medication to clear my spots albeit I've still got some scarring, I finished University and started working full time so I could afford nice clothes, nice haircuts and a nice car. I joined a gym and go regularly to stay in shape. Because of this my confidence grew and I went from a 4 to a 7. Inside however I am the same person with the same friendly attitude but girls pursue me more now. Why's that, because I give them a reason to!
To sum up guys, If you are a nice guy, stay a nice guy but bring more to the table! Don't chase girls, don't become a doormat and for god sakes LOVE YOURSELVES!