I noticed working on a cintiq feels a lot more natural when sketching, so thats something to consider. Also, Krita (Krita.org) with the sketch brushes (type in 'sketch' in the filter bar) makes sketching a lot more enjoyable. There's a happy accident aspect that comes with its brush engine.
if you have a concept or a sketch done on a side view of a gun model, sometimes its very helpful to sketch a design on side view, then use projection to project your designs or sketch on a model and then later on do some illustrations or model highpoly parts based on the sketches you have done.
Hi all, I'm Matt and this is my neat little sketch book I am a freelance artist and I wanted to join the 3d community to broaden my horizon. Here's a bunch of my sketches Feel free to check out my blog also :)