Some superb answers here. I especially like:

Actually, for my money, an expert is someone who has learned enough to understand and acknowledge that he/she does NOT know it all, but has a pretty damned good idea how to find out and where to look...

I think the best way to learn is to commit to a task that you need to, and must, complete. Not something you feel that you'd like to do as a learning exercise and without a real need or purpose. Without the commitment and the pressure, it's unlikely that you will persevere and finish the task. And don't be afraid to try ... what are you going to break? And don't be afraid to ask ... the only stupid question is the one you don't ask. OK, if you keep asking the same question and don't learn, that can start to look stupid

Regards, TMS