I don't really try to search for compliments, but if I do find something impressive I tend to express that it is automatically, even if it's just going 'Oooh!' I have a really hard time giving a false compliment, or saying false things in general.
When it comes to receiving complements (or gifts, or favors...), I've been told that 'thank you' is generally the most polite, and thus I've started saying 'thank you' as my default (as long as I recognize something as a compliment, anyway). Turning something down can be seen as unappreciative, and similarly, I'd think saying someone is 'too kind' or otherwise attempting to be 'modest' can be seen as unappreciative as well. (Unless you happen to be in someplace like Japan, where it's customary to deny being good at something, or generally being deserving of praise/gifts.) Agreeing with someone can be seen as pompous and egotistical.