toward better Arduino customized boards...

Hi, My dream was that I could make customized Arduino boards for new robots, so they are just fit with the need.

I'm no electronic person but trying hard to learn it. Now I finished first step with my customized Arduino and L293 driver boards:



Please if possible give some advice / suggestions how make better boards. I design double sided, use auto-rout for now and then put many vias so that to solder most components only from bottom layer.

One of the first problems I have currently is that I didn't use fuse for limiting current on Arduino because the fuse on the schematic of Arduino is not locally available to me. Could You also suggest some range, specially if through-hole, that I could easier find for the boards please?

I appreciate greatly your attention,