Struggling to differentiate between the guttural sounds – any advice?

I’m an absolute perfectionist when it comes to Hebrew pronunciation, so I record myself reading news articles daily. However, I’ve realized my 'Ayin' and 'Aleph' sound identical to native speakers, and I’m clearly missing the mark on the Hhet/Khaf distinction. I feel like my voice sounds too 'American' despite my best efforts. Could someone suggest a specific drill to isolate the throat muscles, or should I try using Chickytutor.com to get instant feedback on those specific phonetic traps?