These words are sort of kicking my butt, because they are etymologically so different from other languages I have learned so far. I remember having the same problem with Japanese back in the day, and making use of ridiculous mnemonycs to try to memorize them (like ushi (牛) - cow: imagine walking by a meadow and seeing a cow and asking, "who's she?"). I figured I'd share some of the ones I came up with for Swahili so far in the hopes that it might help some of you. Beware: they are really silly... but that's sort of the point.
msafiri - traveler: going on safari (relatively obvious one)
mhandisi - engineer: an engineer is handy, see?
mgeni - guest: honestly, I just go with the similarity in sound of the first syllable
muuguzi - nurse: u good, see? (because I healed you)
mkulima - farmer: a farmer cultivates
mwalimu - teacher: what (are the) limits (of my students?)
mwanafunzi - student: students wanna (have) fun
mpishi - cook: cooking pizzas
mhudumu - waiter: hoe duur (Dutch mnemonic, sorry)
seremala - carpenter: saw or mallet
fundi - artisan: an artisan knows their craft to the foundation.
I can only apologize.