I'd like to consider myself as someone that contributes to the Oracle learning process for aspiring Database Administrators. Oracle is a big piece of software that we all need a little help in figuring out. The one thing you need to remember is someone has done what you are trying to do. When I get stuck on something, where do I go for help?
The first place I usually look is the online documentation at tahiti.oracle.com. There's usually a wealth of information on every little aspect of the piece of functionality you are searching for. The hardest part is filtering out all the extraneous things you don't need.
Next, I logon to Metalink and start searching for documents related to my problem. If you what you are looking for, Metalink is a great resource. My first seach is usually restricted to documents. If that doesn't yield enough results, I'll open it up to the forums as well.
If I still haven't found my answer, I'll navigate over to AskTom. The searching capability on this site is phenomenal. It has five years worth of questions and followup on just about every topic immaginable. If you get the rare chance to ask Tom a new question, definitely take it. You may even want to formulate your question beforehand and check back from time to time to see if he is accepting new ones.
Then I navigate to some other sites maintained by some people I really respect. You might not get a specific answer to your question, but may get some background on the subject you are researching. A great resource for install and "how-to" articles is OracleBase by Dr. Tim Hall. If you're dealing with latches or locking, definitely navigate to Steve Adams's IXOra. Howard J. Rogers site www.dizwell.com also has a lot of information and tips for DBAs and developers. Last, but not least check out Jonathan Lewis' site at http://www.jlcomp.demon.co.uk.
Then I'll start looking at "the forums". There are lots of question and answer forums for Oracle support and you have to pick and choose which ones you trust. I may be a little biased, but I prefer DBASupport.com and dizwell.com. Those forums are usually frequented by people that really want to help. As a hint, the people that answer questions really get turned off by subjects that contain "URGENT".
If all that fails solve the problem, I'll submit a TAR to OracleSupport. You won't get an immediate answer, and you might have to state your problem two or three times, but you'll eventually get either an answer or they can file a bug. If you're not happy with the progress of the TAR, you can always call the main support line and have the TAR "duty managed". Don't "duty manage" all your TARs, but only the ones that are important to business that might not be Sev 1's.
As a last resort, search the web. However, there's so much bad information out there that you really need to have an idea of what the solution is to help you in your search.
If anybody has any additional sites, please post them and share with the rest of us.