WordPress: showing related posts on static page

I recently started to create custom themes for WordPress, but I haven’t figured out the best way to display related posts on a static page. On a few static pages, I would like to show the 3 latest blog posts about that same subject. Should I use the same categories for pages and for posts?

In some other project I would like to achieve something similar. Instead of blog posts, I want to show photo albums of projects related to the subject on the static page. So on the bottom of the page, there are thumbnails per project. When you click on a thumb, the photo appears in a lightbox and you can slide through all the images of that album (so you don’t go to the next thumbnail visible on the page).

Custome themes onto WordPress will give you an option to quickly make a website.
But if you want to go into more details like adding thumbnails and extra stufff then I suggest you use a page builder.