If people do something like taking your place in a queue - I would just in a polite manner note that it is my turn. In many cases people just don't notice you or are just absent minded and don't mind letting you.

If people are aggressive towards you - I would in a polite manner ask them to stop because it makes me uncomfortable; or I would say something like "look at this clown trying to get some attention" so everybody notices his bad behavior, or in a calm manner say "stop it or you gonna have problems" (but you will have to be ready to fight). My key is to battle aggression in a calm, polite manner, that shows you are very confident, plus you think properly when you are not driven by emotions.

You can ignore them. I mean not just be silent, but actually feel that this people have no influence on you whatsoever. It takes some inner game to do this.

All of above advice requires confidence and good inner game. You can achieve it by always confronting people who put shit on you. Practice makes perfect. With some experience you will project confidence and people will stop doing this things to you.

The fastest advice is to start doing martial arts. I would recommend MMA - you practice punching, kicking and wrestling. After few months you will be used to battles and you won't give a fuck if the guy is 3 times bigger than you. It won't matter if you beat him up or you get beaten up, just no big deal.

Ignore him. Not that I'm scared (I don't fear anybody generally), but one picks his battles. Tell him "is there a problem?" I don't let others ruffle unnecessarily. Move on. Whilst the laws of football may say one thing, referees are human and have their own interpretation of things. I may kick him or hit him, but the ref may genuinely not seen his challenge/tackle. Besides, players say lots of things to wind opponents up, it's part of the game. I don't fear confrontation, but I don't always respond with force. Force begets force, and frankly from a legal context it's not wise. If somebody verbally insults you and you hit them, YOU are going down legally, not him. If anything, I will verbally insult the other party until he hits me. That way, I can say in any court that I did nothing wrong and he cannot control himself lol..

I agree with MrGiggles. You have to stand out for yourself, don't let them treat you like that. Show them that you can take them down. Because, if you don't stop them, they continue to treat you like that.

On number 3 I think play to the level too.

If you can run rings around the guy lull him with yr 80% speed and step past. Look at the gridiron guys how they use a tiny hand movement to redirect the guy as they step - works well. Mentally don't get angry use it to raise yr intensity. And shake hands aftwards and mean it. Field is for getting yr T out.

Re martial arts I done a ton. Really only helps yr confidence. I've never been stupid enough to use it.
U do the guy hits his head on the way down and your next g/f is named big Bob. I vote politeness too and use the power of the group. Also maybe close up space a little bit and just pretend u don't see him - sometimes I let a-holes cut in (if they did it with style) sometimes not.