BOB:
Chomps Gate

(1)

WF1:
Shoot into the wild blue
Whomp fight
Tower (select star 3 for cannon strats)
Owl cage
Blast away the wall

(6)

Secret Slide 1
Sunshine isles

(8)

unlock mario
goomboss switch star

(9)

CCM:
lil lost penguin
Slip slidin
wallkicks will work
100 coins + penguin race (if you don't want to do this, do HMC rolling rocks and the silver star level near bbh)

(14)

WF2:
100 coins + reds
switch star

(17)

! block star (and hit the block)
Bowser 1 Red + Switch star (+key)

(20)

Courtyard boos near bbh

BBH:
bookcase secret thingy
unlock luigi + the vanish cap star in there (select star 3, get luigi cap before going in the luigi painting)
merry-go-round (select star 3)
big boos balcony

(25)

switch to luigi

JRB:
sunken ship,
stone pillar
eel

(28)

SSL:
bird
top of pyramid
top of inside of pyramid

(31)

LLL:
All apart from 100 coins

(38)

toad star

HMC:
amazing emergany exit
toxic maze
wario switch star (select a star other than star 1)
re-enter+exit course

(42)

switch to mario

DDD:
chests
sub star
manta

(45)

Bowser 2 reds + switch
re-enter+exit course

switch to luigi

(47)

WDW:
box teleport star
caged elevator star
top o' the town

(50)

THI:
switch star
box at top
pirahna plants
koopa race (pick up mario cap)
klepto
(you can do WDW100+secrets instead of koopa+klepto, but it is rng heavy. w/ good rng saves 5-10 seconds. I don't bother)

(55)

toad star

TTM:
Star at top
mysterious mountainside
reds
mushroom star

(60)

star through the mirror

SSL:
inside igloo vanish cap star (unlock cannon)
snowmans big head
whirl from freezing pond
ice bully

re-enter+exit course
switch to mario

(65)

Secret slide 2

TTC:
All apart from sliver stars

(73)

toad star

RR:
ship
box by chuckya
big house in sky
reds
tricky triangles
swigin in the breeze

(80)

bowser 3