Tip: See my list of the 
MostThese two words are a common source of mistakes. The word you will need most of the time is “analogous”, which means “similar, comparable in some way”, as in
correct The example is analogous to the one we did last time.
wrong The example is analogical to the one we did last time.
correct Those two questions are analogous.
wrong Those two questions are analogical. (probably wrong)
“Analogical”, on the other hand, means “related to or based on analogy”. For example,
correct Roman lawyers had already used analogical reasoning.
wrong Roman lawyers had already used analogous reasoning.
“Analogical” in the first sentence refers to analogies Roman lawyers used in their reasoning. The latter sentence would only make sense if we had spoken about another kind of reasoning before and wanted to express that Roman lawyers used reasoning analogous (similar) to the one already mentioned.
