Part of the reason I took the new postdoc position was because I knew my general cloning skills and biochemistry were a weak point. I think Achilles heel wouldn't be an exaggeration of late!
Seriously, I'm starting to wonder if the phrase "I've forgotten more about cloning than you'll ever know" can be applied to oneself? I'm pretty sure I wasn't this stupid when I was an undergrad with regards to knowing about orientations and reading frames. I've somehow picked up incorrect information. The only positive is that I am learning slowly and usually via really stupid mistakes. Learning a lesson the hard way is often the best way though.
The key thing is to suck up the embarrassment and keep admitting I don't have a clue what I'm doing and then colleagues tend to help although some are better at telling, rather than explaining, Maybe one day I'll have a clue what I'm doing and I'll be able to help others but for now I'd settle for just being able to handle it myself.