Some good tips from the blog “Teach Kids Art” on how to establish a daily sketchbook routine, including suggestions for a lightweight, portable sketching kit. I can second the recommendation for most of these materials as I use them too:

To ensure you have a sketch­book at your side when oppor­tu­nity (or inspi­ra­tion) strikes, you’ll prob­a­bly need to have more than one. Keep a sketch­book in the car, and another one (even a very small one!) in your purse, back­pack, or bag. I like Mole­sk­ine Books.… they come in a vari­ety of sizes and paper types. I love their “squared” books (like graph paper) for sketch­ing, design­ing, jour­nal­ing, and mak­ing lists, and their water­color books, which are great for any wet media. Mole­sk­ines always include a handy pocket inside the back cover and an elas­tic band to hold your book closed.

A few sim­ple sketch­ing tools are all you need.  A mechan­i­cal pen­cil with a hefty eraser on the end is essen­tial! For ink, I like water­proof Pigma pens, which come in a vari­ety of widths (and col­ors.… but I mostly use black). When I want to add color, a small Win­sor & New­ton “Cot­man” water­color set is easy to bring along. A Niji “Water­brush” dis­penses water (stored in the han­dle) right through the bris­tles.… a ter­rific aid for trav­el­ing light with your sup­plies! (Click here for a help­ful tuto­r­ial on how to use a water­brush.) And if you want to travel even lighter, you can use water­color pen­cils to cre­ate a “palette of colors“on a sep­a­rate page of your sketch­book, then sim­ply wet them with a damp brush to lift the color for painting.

Read more at Feed Your Creative Soul – with a Sketchbook! | TeachKidsArt.