Making my Theme Widget Friendly

Hi there, I’m very new to WordPress and I had someone design my template for me. I’ve lived with it for a few months now and I’d really like it to be widget friendly so I can more easily change the sidebars.

Can anyone tell me how to do this? My blog has two sidebars and can be found here: http://secondhandkarl.com/

Appreciate any and all help. Thanks.