Improving your body and mind are the easy parts. Just work out to become stronger. Just learn stuff to become smarter. Just practice things to become more skilled.
You can improve the way you look, being near some gross hobo looking dude makes people uncomfortable. Getting a haircut every couple months, taking a shower more than once per week, and wearing proper clothes makes you a much more respectable existence. Doing so doesn't require you to have or know or learn anything, it's just stuff anyone can do at any time, it's more of a discipline thing than anything else. As a bonus this also makes it easier to think better of yourself and have maintain a proper mindset.
The hard part is how to become better in mental and philosophical aspects and in behavior.
Not littering is better than littering. Cleaning your room is better than not cleaning it. Returning the shopping cart is better than not returning it. Being quiet around other people is better than being loud. Loitering around on paths and hallways is worse than doing so somewhere out of the way. There's all kinds of little things you can do in daily life that either slightly improve the world, or prevent it from getting worse, you should have the will to do these things even without being asked. If someone has to even think about asking you to do it, you've already become a tiny force for evil who made the world a bit worse.
You can directly improve the world around you. For example there's a shortcut near my apartment that's surrounded by bushes and trees. I occasionally prune the branches and bushes so it's easier to go through (it's surprising how quickly tree branches grow back after being cut), and clear the snow in the winter and spreading sand on the ice (there's a box of sand near my apartment, nobody told me if I'm allowed to use it and I never asked, I just use it). There's some old people who have directly thanked me on a couple occasion because it helps them too, not just myself, and after I started doing it I noticed other people have sometimes cleared the snow before I did. If some faggot littered in your area, you could be the one to clean it up instead of waiting for a mysterious force to do it while you continue to look at trash for an undetermined amount of time. You can Just Do Things™ and improve the world around you, you don't have to ask anyone.
>caring
>empathetic
>respecting
>avoid acting with malice
All of this sounds good in a vacuum, but excusing evil makes you no better than evil itself. Evil and malice and greed don't exist only in movies, the world is full of it. Be good towards the good, be bad towards the bad. If you can make the world a better place, that by definition makes you a greater person. You can foster good in the world by helping good people and good causes, but helping the forces of evil will make you a force of evil as far as the world is concerned, even if you thought you were doing a good deed. "Being mean" is thought of as a bad thing because our society is too much of a feminized fag fest, but if you can destroy evil, that makes you a force of good, not a force of evil.
Things are complicated a bit by the fact that some people on the side of evil are not inherently evil, they are victims of propaganda. If you can save them, that's obviously better than killing them, but if you can kill them, that's also better than letting them spread evil. You can also kill someone's evil without killing the person, for example if you can make someone and their words look dumb and unlikable, their ability to spread evil is reduced, in fact they may do the opposite by making other onlookers look down on evil.
In some situations it's very difficult to say what's the right thing to do. For example I mentioned that cleaning up litter is good. However, if there's some nigger who continues to litter, if you clean it up then you're just helping that nigger be a force of evil and not face any consequences for his evil behavior. But if you leave that litter be, then perhaps you'd be playing one tiny part in a wider overton window shift that would cause people to eventually get rid of or punish such forces of evil. But if it's just some one-off thing of kids being retarded, then it's not worth looking at that trash forever.
Similarly, saying words like "nigger" is degenerate, and certainly makes the world worse for the good black people out there who just want to live their lives in peace and play videogames like we do. Hell, I could be talking to a non-white who's trying to become a better person right now, and there's no reason for me not to respect that. But on the other hand, western societies have gotten so irredeemably bad due to brown people being used as a biological weapon that trying to be kind may do more harm than good. We're far past the point where one should start fighting back, and shit's basically unfixable without a radical purge or a race war. When you're aggressive towards them, you may be spreading the mentality that it's ok not to give everything to them, which may then become a component to change things in the future. When you're interacting with someone on a personal level, try to match their kindness, but if you're talking on a societal level, it's probably better to be unkind.