< No spoon feeding >
Search before asking. The people at the discussion forum aren't getting paid for answering your questions. They're hanging around there to learn new things and help others when they feel so, and they don't like seeing the same "How do I change my default window manager" posted a million times.
Most likely many people have had the same problem as you, and there is excellent documentation answering your question. Google is your friend. Use it before abusing any discussion forum.
The discussion forum where you're about to post probably has a way to search the topics posted before. Use it. Chances are that somebody has asked the same question before. If someone's asked the question recently, the people at the forum don't feel like answering a lazy person asking exactly the same thing.
Show you've searched. If, after searching, you haven't found an anser to your question, then post. It's a good thing to mention in your post that you've searched for the answer but haven't found it. For example, a post starting with something like "I searched Google, relevantwebsite.com and relevantwebsite2.com and this forum, but didn't find anything..." gives a good impression.
If you found documentation about your problem but following its instructions didn't help, or you didn't understand it, mention that in your post too. For example "I followed the instructions described in website.com/helparticle.html but using command XYZ like they suggested didn't help, instead I got an error message saying this..." or "I found some good instructions with Google, but they were too technical and I didn't understand what they meant. Could someone explain to me what they meant by XYZ or could you point me to a more newbie-friendly resource..."