acrylic nails keep cracking on the sides!?

heyy, i get my nails done by my moms friend. she's honestly kinda amateur and does her stuff at her house. she's really not so bad and because we're friends, it's cheaper than most. however my nails keep breaking off at the tip and cracking on the sides. i swear that it's not my fault, when my nail tip broke off i was walking around a store! i want to know what is she doing wrong so i can watch for it and tell her otherwise or maybe if im doing something wrong to encourage this breakage. it's really frustrating and i'd like to know what's causing it and what can be done!