I'm struggling with how to make the most of SO. Specifically:
Common convention on the Stack Exchange network is that you ask one question per post. I'm not personally sure how well enforced this is on Meta, but please don't post these kinds of questions on Stack Overflow.
I'm struggling with how to make the most of SO.
It's quite simple really; This is a Q/A site. You either have a question you want an answer to, or you are a programming enthusiast and want to challenge yourself or give back to the community by answering other pople's questions. Reading the FAQ should get you started.
1. How can I only see specific questions (by default) that I am interested in?
That depends on what you mean. If you want to see questions with specific tags, you should add those tags to your list of "interested" tags in the sidebar. If you want to be notified when specific questions change or receive new answers, you can favourite them by clicking the star under the voting arrows.
2. Is there some sort of email integration?
You can subscribe to tags, and receive a periodic email containing the top-voted questions for that tag
3. Does the SO network allow me to monitor (contract) jobs in London?
Careers supports finding jobs by location.
4. Can I somehow 'tag' questions that I like for future reference?
See my response under #1 about favouriting questions.
