Don't be afraid to get it wrong.
While it may not be a great thing to admit but some of my best lessons have come at the result of initial failure, taking a backup before deleting all the data in a table comes to mind. When I first started this blog and even more so when it was added to PlanetMySQL I made a decision that not being 100% sure about something wasn't a reason not to post it. Don't get me wrong I always make every effort to check my facts and in the Tom Kyte mode I'll always (or at least try) and give real world examples to prove my point.
But there are often times when I'll post something which is inaccurate or just plain wrong. There are broadly two things you can do in such circumstances when people correct you (and believe me they will), you can accept you made a mistake, correct any errors and learn from it. Or you can just give up and never post again for fear of looking a total fool. The fact I've made mistakes and I'm still blogging will give you some indication of which group I fit into.
This slightly confessional blog is in response to a post I made a few days ago with regard to XML and MySQL. The central theme was a vision of MySQL as a key component in AJAX where rather than the added complexity of a language such as PHP, PERL etc MySQL took on the role of serving the XML directly from the web server. In it I pointed to Oracles SET MARKUP HTML command and longed for a MySQL equivalent, or at least an equivalent XML version. If you read the comments on that post you will see that MySQL does support such a feature, it's not exactly what I was talking about but it's close enough to have been mentioned. I'll say that I was at least in the past aware of the feature but when I was checking out my facts prior to posting I couldn't find mention of it on the MySQL site, I just thought I was mistaken and it was a feature of some other software.
The point is that you shouldn't sit in the shadows fearful of getting something wrong, if you have been worried about blogging or answering questions on forums for fear of being wrong you won't get very far.
Yesterdays mistake makers may well be tomorrows experts*
*Providing they learn from those mistakes.