In addition to the many good ideas above, if you roof vent covers that are installed over your roof vents, open them. If you do not have roof vent covers, get them...they are not that difficult to install. In this rainy NW climate I keep my roof vents open 24/7/365, even when we are underway. Allows moisture to exit and we experience no inside condensation since I started this practice 11-12 years ago.
Unless you have a leak as several have mentioned, the above should greatly reduce or eliminate condensation as the culprit.