I've found, the shorter the LARP, the more I have to play things as a caricature, because the less time you have to get your point across. Still, a single glance, or an offhand mention thrown into a conversation -- or even a Freudian slip with the person present -- can be enough to give insight into the relation, and then you never have to mention it again.

I guess I also try stick indications of my character's relations with someone into interactions with *other* people, because in a small LARP it *will* get back to them, or they'll overhear you...e.g., I "accidentally" talked about A___ a number of times as if I knew her to people, even off-handedly calling her "mom" once to someone who had no clue what that could mean; but someone nearby heard, and took the hint well.

Also, the point of infatuation with a person is not necessarily just to about *them*; it's about everyone you both interact with. E.g. Kevin's infatuation with Sarah affected my character, despite me not being involved with either of you in a romantic way. Your reactions there were definitely useful to help me roleplay...