Mental Considerations
Solving cryptic clues uses both left and right brain skills. I am going to use the normal definition - left = analytical, language; right = intuitive, pattern recognising. Using this, most of us are more left brained than right.
Some say that we are at our most creatively effective when our brain sides are equally empowered, which for most would mean lowering the left, or increasing the right. The classic way of achieving the former is meditation; for the latter drumming and dance.
I’m in the first group so I need to be relaxed. In fact, the more I can shut everything out the easier it gets. My right brain or subconscious can feed answers from nowhere which it can take me a while to actually validate. Sometimes I even reject such words, only to find later that I have missed the vital connection.
If you are someone who studies with loud music on, then that is probably the best way for you to tackle cryptics.
Which brings up the question - what do you concentrate on, the Definition or the Wordplay? After you have made the preliminary division of possible Definition/Wordplay I would advise don’t get too analytical too quickly. I believe the right brain’s pattern recognition is capable of extremely convoluted connections (like jokes), and you need to give it space. If nothing comes up then start working.
If you are the type of person who is like a walking thesaurus, start listing words of the right length which match the Definition you have decided on, and which use any letters you have. Sometimes you will see an Inclusion or Addition which you can immediately test against the Wordplay. This method can be used even when you are not sure of the Definition - by listing any words of the right length!
I fill in a crossword with capital letters, and as I have said previously, my brain works best with lower case. And definitely better horizontally than vertically. So if I have a troublesome clue, I will write out what I have in this form: --m--i--s. If I try to do any analysis, I will probably concentrate on endings. But mostly I will just look at it hoping my right brain throws up something. Whatever does arise needs to be tested against the Wordplay.
I am a more analytical than list oriented person, so I probably work more with the Wordplay. I look for indicator words and the subdefinitions they are manipulating. Then I will write out: --met----, or ___met___, the form depending on whether I have an idea of where the subdefinition goes. With possible anagrams I write the letters horizontally, alphabetically in lower case.
Mostly of course, it is a combination of both approaches. I generally go with what jumps out at me first. As I have said, most Anagram indicators are reasonably obvious, so if I can find the right number of letters I will work on them. Quite often in the early stages of a crossword, most of my answers will be anagrams.