People will upvote your question based on it's quality, so put some effort into it. If you don't get any answers to your questions keep at it, you can edit as often as you'd like. This will give it a natural bump, and people will be able to watch your progress in adding more detail. People tend to help/upvote people who are actively trying to investigate their problem.
As soon as you post your question people will leave answers and comments. Comments are like "meta" for the answer - do NOT reply with an answer or another comment, having a conversation here is difficult and it's designed to be that way -- when people ask you for more detail edit your original question and add all the information there. People will then update their answers. You'll continue in this ping pong manner until your question is answered.
One question per question. It's easier to search for duplicates and to vote for the quality of answers when you ask one question per post instead of one huge post with multiple questions.
You don't need to put "Ubuntu" or the version in the question title, use tags instead. For example, instead of "How to install foobar in Ubuntu 10.04?" you can say "How to install foobar?" and tag it with [foobar][foobar] [install][install] [10.04][10.04]. This makes the questions easier to read on the front page.
The more detail the better. "Sound doesn't work" or "A question about firefox" doesn't tell us anything. Your title should be clear and easy to understand. As you are investigating your problem feel free to edit your title to make it more specific, this will help it get the attention it needs.
As you add to your question, if you end up finding the answer, then answer your own question (example) so that future readers can benefit from it!
If someone answers your question, accept it as the answer. This is an important part of the process and rewards the people trying to help you.
Not getting the help you need? If you're not getting answers to your questions (or at least upvotes) then it could be that your question is too difficult to understand. Here are some tips on improving your questions. Keep at it, the more detail you add the better chance we have of helping you!
Try to give people an easy to understand answer, adding screenshots is a great wayadding screenshots is a great way to help people. Here are some toolssome tools to help you. The site itself handles image uploads, so you don't even have to worry about that.
When recommending software link it to apt.ubuntu.com so it's easy for people to install.
Don't only link to random sources on the Internet. Any person can type their question into Google and do that. If the information is good and under an open license, just put it in the answer (don't forget to link to and attribute the author). Try to make your answer the definitive answer to the question and also send them to the official documentation your team supports.
Edit, edit, edit should be your mantra. — If you've got a good answer and someone adds more detail, integrate it, and remember to always respect an individual's work.
Ubuntu has existing teams that work very hard on documentation, take advantage of them, try to find and link up existing Ubuntu documentation when you can.