As a city dweller in a densely-packed urban core, the hardest part of my day (besides taking a shower) is the commute. It is a naturally disturbing, somewhat disgusting necessity brought on by the double whammy of urban sprawl, and our desires not to live in crates at our respective places of business. For many of us, the hassles of using automobile transportation have led us to chose our cities' public transportation options. Whether buses, trains, watercraft, monorail, zip lines, dog sleds, or even high-powered cannons, each of us encounters unique challenges on our way to and fro. You've grown weary of tourists, suburbanites, teenagers, and people who are not constantly paying attention to their surroundings. As nice as it must be for some people to take all the time in the world to get to where they are going, you don't have this luxury. Time is money (or something)!
This writeup is presented as a learning tool to help you overcome these obstacles, become more efficient in your commute, and make it to your desk relatively unscathed. Not all of these approaches will apply in all cases. Use your best judgment, and if you can't be good, be careful.
Be polite when applicable: Many other guides will tell you to jump straight in with violence, and let the cops sort things out after you're long gone. However, sometimes a curt "excuse me" will work just fine, and be less messy. Usually, folks are in your way because they do not pay attention to their surroundings, and will scurry off when their shortcomings are highlighted. I recommend this technique first, and then following up with violence as needed. In fact, this is a good cardinal rule for life, as well as commuting. Aggravated? Fine. Until then, be drinkable.
Speak softly, and carry a pointy stick: I recommend an old-fashioned full length umbrella (sarin-tipped recommended, but not required), but a stylish cane or cattle prod will work just as well. Whatever you can use to gently guide folks out of your way, and give them a little business if they need a bit more encouragement. Carry it blunt end forward, giving off an air of "I don't want to give you the pointy end, but I will if I have to."
The Messenger Bag, a commuter's best friend: Not only does a messenger bag work for taking things back and forth from home and office, it also makes a good club in case of emergency. I recommend carrying around a significant amount of spare change and paperwork in your bag, even if you don't need it most of the time. This will add to the impact, and not raise the suspicion of the police, should they become involved. For women, you have been using this technique with shoulder bags for some time, so this is not news to you.
Show no fear: Your fellow commuters can smell fear. You need to make sure that these people know that getting in your way might lead to an uncomfortable encounter with a fire hydrant. Sunglasses will help with this look, especially when traveling underground. Work your wardrobe for something stylish, but utilitarian enough that it gives a hint of concealed weaponry. Do not sit, even if there is a seat. Stand there the whole time and peer at your fellow passengers with a look of mild contempt.
Fight for the door: For those of us who take our commuting very seriously, being efficient is the most important goal. Why get on the train or bus willy-nilly when you know where you'll need to go once you're arrived at your destination? This is why planning ahead is key. Board the train in the optimal car, and fight to get that spot near the door so that you can be the first one off. If there is already someone there, try lowering your shoulder and scraping them out of the area. If they are serious about keeping the door spot, you can consider them a fellow professional commuter and cede the spot, because they will quickly be out of the way when deboarding. But be sure to take notes: if they cause undue delay, be sure to assert yourself more forcefully next time around.
Be imaginative: Reevaluate your path every once in a while, to make sure that you are taking the quickest route. Is there an alley that you can use as a shortcut? Is there a building lobby that is clear of obstacles? How can you use construction zones or curb edges to their fullest potential? Is there another door that won't be clogged with idiots, even if it means walking another block?
A note on jaywalking: Efficient commuting means that, inevitably, you will jaywalk. This is a fact of life. However, with the exception of a Giuliani regime ruling over your town with an iron fist, there will be little police action on your little jaunt out into traffic. Just remember to watch traffic, jump your signal, and assume that the crosswalk will be full of people that will be in your way.