Whatever the provocation, keep you mask of good manners intact.
Behave impeccably at all times. Whatever the provocation, keep you mask of good manners intact. Whatever else you do, ensure that both you and your partner present a united front.
Alternatively, you can go for the out-and-out admiration defence. Instead of reacting with insouciance, just turn your face into a mask of awe-struck admiration, sit (figuratively) at their knees and ask them to teach you everything they know. Alternate intent listening with nauseatingly effusive compliments, and they'll soon get fed up with the mentoring role.
Whenever possible, ask for advice from your in-laws (for example on financial or house-related matters, or parenting). They will feel flattered to be asked - everyone likes giving advice?.
Similarly, be very careful about criticising your in-laws to your husband/wife. This isn't necessarily a no-go area - some couples find criticising their parents' behaviour both therapeutic and helpful - but you need to be sure that criticism isn't going to elicit a defensive reaction, or come back to haunt you.
Take the lead from your partner when it comes to relating with your in-laws. You may enjoy chatting to your mother every day, while your husband rings his once ever six weeks. Don't berate him for the lack of contact; accept that every family dynamic is different.