These ink-based "watercolor" pencils are my favorite. I suggest starting with the 24-count set, but you can decide. Here are the links on Amazon.

Derwent Inktense Pencils: 12 Color Set.

Derwent Inktense Pencils: 24 Color Set.

Derwent Inktense Pencils: 72 Color Set

 

These are easy to use, no mess (other than sharpening) and are an essential part of my art travel kit.

Some samples of art made with these.