Across:
1 Deceive oneself into thinking introductions (“deceive oneself into thinking” introductions/first letters = DO IT) sound like (= homophone indicator) author’s pitch (“buy” the book = “BY” THE BOOK) (DO IT BY THE BOOK) to follow every rule, word for word (DO IT BY THE BOOK),
10 German (OTTO-) worker (-MAN) (OTTOMAN) from 23 across, for example (“sultan” was an OTTOMAN),
11 Found on the road (CAR-) and found on the sea (able-bodied seaman = -AB-) with a (-A-) duck (-O) (CARABAO) and water buffalo (CARABAO),
12 Set up (set-up = HOAX) housing loan from Halifax banks (“housing loan from Halifax” banks/sides = HOAX),
13 Grand (1000 = M-) quarter (one quarter of compass = east = -E-) near river running south (River -LEE) (MELEE) in Donnybrook (donnybrook/uproar = MELEE),
15 Crazy (nuts = STUN) about (= reversal indicator) what Taser can do (Taser gun can STUN),
17 Have a look inside (x-ray) Trim (trim/cut = x) (“x-ray” without “x = RAY) for a touch of sunshine (RAY),
19 Raise the issue (TAKE UP) of adoption (TAKE UP),
21 Socialise (mix) briefly (x) (“mix” without “x” = MI-) serving up (= reversal indicator) goose (bird = -DRIB) (MIDRIB) – you’d need to turn over a new leaf for that sort of gander (gander/look at vein in a leaf = MIDRIB),
22 Old comic (Beano) almost (o) (“Beano” without “o” = BEAN-) gets sack (-BAG) (BEANBAG) for lying about in the lounge (BEANBAG),
23 Sovereign (SULTAN) and soldier (Lieutenant = -LT-) with a (-A-) place in the sun (SU-N) (SULTAN),
25 Mystery man (X-) and (AN-D-) a (-A-) trespasser from university (-U-) (XANADU) in idyllic place (XANADU),
27 Characters in Clint Eastwood’s (characters in “Clint Eastwoods” = TEA) Rosy Lee (Cockney TEA = Rosy Lee),
29 Very small (IOTA) item on the agenda, for starters (“item on the agenda” for starters/first letters = IOTA),
30 Misjudged (ERRED) bottle of Sancerre decanted (bottle of “Sancerre decanted” = ERRED),
31 Some sublime attempt (some “sublime attempt” = MEAT) dismissed by the vegetarian (MEAT),
34 Specialist (HOTSHOT) heated small whiskey (HOT SHOT),
35 A (A-) couple of lines (-LL-) from paper (-STAR) (ALL-STAR) by top hurler (ALL-STAR),
36 Party (DO) for a (A) detective (DI-) has One Direction (south = -S-) and The Cars – check (the car’s check = -SERVICE) (DO A DISSERVICE) what’s the harm in that? (DO A DISSERVICE).
Down:
2 What general would do to colonel (OUTRANK) to redesign (= anagram indicator) our tank (our tank = OUTRANK),
3 Period (TIME) in some Djibouti metropolis (in some “Djibouti metropolis” = TIME)
4 Deny or (deny or = YONDER) process (= anagram indicator) over there (YONDER),
5 Gamey type (HOCKEY) of horse at first (“horse” at first = H-) loses top (j) rider (“jockey” without “j” = -OCKEY) (HOCKEY),
6 Part of the scuba reconnaissance (part of the “scuba reconnaissance” = BARE) is with nothing on (BARE),
7 Tribe or (tribe or = ORBITER) movement (= anagram indicator) travelling around the world (ORBITER),
8 How to catch eye of the man upstairs (DO WHAT IS RIGHT) is not bad advice (DO WHAT IS RIGHT),
9 What square bashers accomplish (square-bashers /military drill on parade ground = DO AN ABOUT TURN) to achieve revolutionary change of heart (DO AN ABOUT TURN),
14 Run deal (run deal = LAUNDER) freely (= anagram indicator) with clean money? (LAUNDER),
16 Singer comes out of gas turbines (“singer” comes out of/ removed from “gas turbines” = atubs = TUBAS) with big brass instruments (TUBAS),
18 Capitalise on capital (capitalise on “capital” = C-) from Riga (Riga = -IGAR) moving (= anagram indicator) (CIGAR) to The Big Smoke (CIGAR),
20 Bit of compensation (bit of “compensation” = PEN) for the writer (PEN),
21 Biggest (MAX) taxi-man ain’t leaving (“taxi-man” without “aint” = axm = MAX),
24 One will have to move on (LET IT GO), as one didn’t put hand out for bus (LET IT GO),
26 A (A-) poisoned (-SEPTIC) (ASEPTIC) type who won’t give you anything (ASEPTIC),
27 Tory leader (“Tory” leader = T-) finds roots (“roots” = “Ruths” = -RUTHS) reportedly (= homophone indicator) (TRUTHS) – no lies! (TRUTHS),
28 Add a touch of sparkle (AERATE) as Judge (-RATE) Russell (AE-) is up first (= position indicator) (AERATE),
32 Take off (SHED) shrink-wrapped sides (“shrink-wrapped” sides = SHED),
33 Some gorgeous lavender (some “gorgeous lavender” = SLAV) found in The Balkans (SLAV).