The suggestions about material above are all good and needed. Here is one that was not mentioned, and may be as important as the others, if not more. There needs to be some spiritual clarity about who the other one is. IF the boy was put into the shidduch market as a learning boy, there will be an expectation (a reasonable one) that he also make it to minyanim on time, and not be busy with extremes of gashmiyus, technology, etc. If he is more “with it” and this violates the expectations the kallah had, the trouble has where to start really early. If the girl was put on the market as a really ruchniyusdige girl, and she is not, another trouble spot.
Basically, the masquerades that are employed to pull off shidduchim are potentially very destructive.
Couples need to have an approach to marriage that is much deeper than friendship. A shocking percentage of madrichim spend no time on this subject. Love should be a major discussion, not a passing mention. Expressing affection should also be addressed directly and openly. Remember, we have few role models on such matters (if any).