What kinds of phonemes and sequences do you think are easy to learn and use for the majority of people?

This is a question that I keep trying to work out for my language so that most people, regardless of their linguistic background, might be able to learn it. For my language I sort of went from the most common consonants and vowels /i e a o u p t k m n/ and tried building a phonology based on the places and manners of articulation it provided, though I'm probably going to revise it since it's not be as easy to distinguish some of the sounds as I'd hoped, like the nasal series /ŋ ɲ n m/. Also /ʔ/ isn't easily approximated and doesn't flow well.