Forums and communities
We all get stuck from time to time. In many cases, someone else has already encountered the same problem and solved it. This is what communities are for, people helping each other out. There are many communities out there; the ones I participate in are the Microsoft MSDN SQL Server Forums and Stack Exchange..
Also, Microsoft has a great page summarizing options for asking for help and providing feedback to Microsoft.
Please read this before asking for help
You can greatly increase your chance to get a good answer by following a few simple recommendations:
Use your search engine!
Do some investigation first. The forums are not there to replace the documentation that comes with SQL Server. The activity on these forums is very high, and this results in some questions being unanswered. If you want to be a good community member, do a quick search using your favorite search engine, in Books Online. You'd be surprised by how many questions are posted that can be answered immediately after a few seconds of searching. But please don't take this as a discouragement to post.
Be as precise as possible. Spend some time writing your post. Tell us what you have tried, the symptoms, and if possible how to reproduce your problem. The more information we have, the better chance we have of helping you.
If you have T-SQL problems, help us to help you. Have you tried to do "dry programming"? It is very difficult. Most programmers want to run the code they write. Please post the CREATE TABLE statements for the relevant statements, including constraints but please remove things that make it hard to read (like COLLATE clauses and stuff like that). Also, post INSERT statements so we have something to work with. And the desired result.
Include details about your SQL Server version, service pack, OS version and other relevant information.
Have a descriptive subject. Also, make sure that the question is found pretty early in the text.
Finally, here's a great link to how to post good questions in community forums. Most are actually only common sense and politeness.