Struggling to hear the difference between 'ich' and 'ach' sounds in native audio

I’ve been recording myself reading German poetry for weeks to try and perfect my accent, but I can't quite nail the 'ch' sounds. Whenever I listen back, it sounds harsher than what I hear in native content. Does anyone have specific tips for tongue positioning, or should I maybe use Chickytutor.com to get automated feedback on my pronunciation samples?