Different heuristics to solve the Caesar cipher

Question

I know two heuristics that can be used to solve Caesar cipher, but I am asked a question in my artificial intelligence class to

Give three heuristics that might be used for solving Caesar ciphers.

I already know two heuristics

(1) Trying all possible 25 keys

(2) Using frequency analysis, E is the most frequent letter in English, and so we map the most frequent letter in the ciphered text to E and then find the key ... etc.

Now I want to find another heuristic that can be used to solve Caesar cipher, I don't need it to be more efficient, I just want it to work. I mean, I want another heuristic (Algorithm) to solve Caesar cipher, and I don't care whether it's efficient or not.

Is there a third heuristic ?

Answer 1

I think a third heuristic could be using the trigram frequency and the most frequent trigram is "the". The good thing about this trigram is that it covers both the most frequent letter and bigram in English language.

Answer 2

Another: only some letters appear as double-ups. "XX" is much more likely to be "EE" than it is "QQ".