The default rule
Most verbs simply add -ing: READ becomes READING, TALK becomes TALKING, and VISIT becomes VISITING. Begin with this default and change the spelling only when a specific rule applies. That keeps exceptions from making the whole system feel arbitrary.
Drop a final silent e
MAKE becomes MAKING and WRITE becomes WRITING because the silent e is normally dropped before a vowel suffix. Keep e when it protects pronunciation or identity in cases such as DYEING, which is distinct from DYING. The visual difference carries meaning.
Double the final consonant
A one-syllable consonant-vowel-consonant verb usually doubles its last consonant: RUN/RUNNING, SIT/SITTING. Longer words double when the final syllable is stressed, as in PREFER/PREFERRING, but not when it is unstressed, as in VISIT/VISITING. W, X, and Y are not normally doubled.
Change ie to y
DIE becomes DYING, LIE becomes LYING, and TIE becomes TYING. This small family is worth memorizing because ordinary “drop e” reasoning would produce misleading forms. Build a personal exception list from errors you actually make rather than collecting every rare case.
Quick review
The strongest habit is to separate hard constraints—letter counts, length, fixed positions—from helpful clues such as frequency and familiar patterns. Use the tool to narrow possibilities, then use meaning and context to choose.