Verbs of utterance
There are many words in English meaning 'to say', with different shades of meaning (examples include 'to mention', 'to argue', 'to define' etc). Avoid them all. 'To say' is the best, even if you are tempted to think that it is dull or repetitive.
Speakers of English as a foreign language often start to use less simple verbs as their confidence increases. Try not to. Stick to say.