Lesson 1: choose your materials carefully.
I am not a natural DIY expert. Here's my latest project: a blackboard for Ainsworth to use in the garden.
I think it went pretty well. Three panels of wood sanded and coated with three coats each of fancy and expensive blackboard paint (magnetic, no less!) carefully attached to two batons and attached to the outside wall. It was fairly level. With no drips. And he loved it.
And then the rain came.
Wood warps when it gets damp. Well, cheap wood does anyway. Badly. And falls off the wall as a result.
Back to the drawing board...