N00b cryptic solver here. I got thru this puzzle with a few guesses, but I'm far from understanding what's going on. I read your explanations, and some of them made sense, but others are opaque to me. Is there an online resource for cryptic solvers that would help a novice parse "O+(SH+TA)<" for example?
I’ll presume you’ve read Crosshare’s intro to cryptics page, which is a nice overview to pretty much all the ‘methods’ of wordplay you’ll come across. The tricky part is working out what each word is telling you to do, and I think particularly steep in the learning curve is abbreviations and short synonyms. In the clue you’ve pointed out, for example, Quiet = SH, thanks = TA, that is all returned (i.e. written backwards), following (after) ocean = O (abbreviation seen e.g. on maps). The shorthand explanation notation isn’t standardised and is just a fairly succinct way to show you how the answer’s built, you still have to identify which clue words are doing which bit.
I think the Crosshare primer is enough to get you started, and beyond that it’s just practicing identifying the words. I use this as a resource for wordplay indicators and abbreviations etc.: http://www.clueclinic.com/index.php/clinical-data/
Cryptics can be hard, and starting out some of the abbreviations will seem annoying and arbitrary, until suddenly one day they’re automatic. I think the best way to improve is to familiarise yourself with the basic wordplay elements, then just keep trying. On Crosshare, feel free to ask people for parses on clues that seem murky, they’ll be happy to clear it up. Hope that’s useful, and thanks for solving!