Look at the end of the word. Sort by it's suffix.
grinned
peeking
winked
gripped
slogging
sloping
beginning
gulped
stunning
spotted
-ed
-ing
blab
blab
Do you need to double the consonant?
heap
heap
Do you need to double the consonant?
hug
hug
Do you need to double the consonant?
Add -ing
Add -ing
Add -ing