Any tips for understanding slurred speech?

Sometimes I’ll be listening to a native speaker talk, and they’ll fly through a sentence and not really annunciate everything very well. Sometimes I’ll try backing up and listening to it again in slow motion, but it still sounds almost completely unintelligible to me. I sometimes use subtitles to help me, but at that point I’m just reading more than listening.

I know this might be a difficult thing to learn, but does anyone know of any practical tips for developing my ear and being able to understand imperfect speech better? I know obviously practice, but any tips on how to practice most effectively? Are there any specific sort of things in the speech I should listen out for or whatever? Anything like that?

Thanks!