Building Science Corporation is a great resource for serious DIY'ers. It has a large library of construction articles and reviews.
My current project, a patio cover, needs to be connected to the house properly to ensure we don't get water problems leading to rot (especially in western Oregon). I referred to a number of articles on siding and flashing to make sure I did it correctly, and that it would compatible with a "rain screen" design that I will be adding later.
Here are a couple of images from an article on water management I used:
The picture above shows basic drainage plane design, while the one below is how to flash a window to ensure any water that gets in drains back out again with no damage. In this case, my patio cover roof connects to the house right under a window, and I wanted to make sure the roof flashing would connect properly to the window pan flashing.
Disclaimer: The main focus of this blog is documenting my own DIY projects. When I do feature a site, it's one I have personally used, find useful, and is not sponsored.