Down
1. Foot doctor? (5)
2. Premed is, I worried, thin of skin? (9)
3. Genetics or manipulation of a hormone (10)
4. Geniuses' story supported by Bible's (7)
5. Numbers some trumpet as a panacea (7)
6. Flu-related seizure? (4)
7. Brief illness is a signal to save time (5)
8. Ahead of the curve and almost all of minnisters' finances? (9)
13. UN's fear -- STD may also spread through supplied blood (10)
14. OB needles adapted for a common complaint (9)
16. Method employed to reduce sorrow (9)
18. Family-run AECL organization! (7)
19. Justification for the good doctor's routine (7)
21. Good guy having a day around home (5)
23. Sound becomes sound of stilettos (5)
24. Rich and rummy (4)
Most cryptic clues can be viewed as an equation. One side of the equation is the definition. The other side is either another distinct definition or a cryptic construction of the letters in the solution. At times a clue can be solved by identifying the definition, finding a synonym for it and then using the rest of the clue to confirm it. Alternatively, a word may be built from the cryptic side of the equation and then checked against the clue's definition.
The common types of clues are anagrams, containers, word chains, homophones, curtailments, double definitions and puns. Punctuation and keywords are two types of embedded hints. A question mark following a brief clue may suggest a pun or wry element, and commas may divide a clue, but they may also mislead you to divide the clue in the wrong place.
Embedded keywords help to identify a clue's type and tell the solver how to construct the solution in a very literal fashion; however, there is no sure way to identify a keyword or clue type. The keyword "mix," in the case of an anagram, tells the solver literally to mix the adjacent letters. A container clue might be signalled by a word such as "held," suggesting that one part of the clue holds another part in the solution. A sound or speech-related keyword might suggest a homophone, e.g., "I said" could indicate "eye." Curtailment clues may have a keyword such as "endless" or "partly." Word chains, which link two or more parts to form a solution, do not necessarily have keywords, but a word such as "after" might tell you that one part of a clue goes after another. Double definition clues do not have keywords, but their brevity can indicate this type of clue.
Cryptic crosswords play on the flexibility of the English language, so the solver must be flexible in approaching a clue. Divide clues in different ways and look for different meanings for words within the clue. If one approach fails try another, and another . . . .
Down
1. Double definition. To foot a bill and doctor a patient.
2. Anagram. "Worried" is the keyword calling for change to "premed is I." "Thin of skin" is the definition.
3. Anagram. "Manipulation" is the keyword, "of a hormone" the definition.
4. Word chain. "Geniuses" is the definition. "Supported" suggests a tale on top of the New Testament's.
5. Word chain and curtailment. "Panacea" is literally what "some trumpet."
6. Homophone. "Related" is the keyword. Look for something that sounds like a word for the flu that could be catching.
7. Word chain and container. "Brief illness" is the definition. "Save" is the keyword.
8. Word chain and curtailment. "Ahead/curve/almost all" is the construction.
13. Anagram. The definition is "supplied blood," and "UN's fear STD" the letters to spread.
14. Anagram. This complaint has the "adapted" letters of "OB needles."
16. Pun. A method employed to reduce or a word for sorrow.
18. Anagram. Organization of the letters in "run AECL" will yield a "family organization." The exclamation mark indicates that part of the clue is serving double-duty.
19. Word chain. "Good/doctor's routine" is the construction for a synonym for "justification."
21. Container. "Good guy" is the definition, "around" the keyword.
23. Homophone. "Sound" is the keyword. "Becomes sound" gives a homophone for "stilettos."
24. Lush. Double definition.