Getting your parents to stop smoking is a very hard task.It took me YEARS to get my dad to stop,I just had to find the right method and attack. It may take a while to do this.Below I listed a few ways to help,I suggest you try each one for a while.And remember,when you get her to stop she will probably getting really frustrated and mean but don't worry after awhile she will stop this,it is a very hard time to go through.
1)Take pictures of you,family,and pets then keep on taping them to her cigaret boxes. Also,you could take pics of heave smokers that look horrible and tape them to the cartons,put up list of names of people who died from lung cancer.
2)Hide the lighters,not the cigs.
3)You said it was hard to talk to her but this is your mother,she is killing herself!Find the courage to sit her down and tell her how you feel. Keep on stating the facts about what cigs do to people, show how you feel not only in words but by facial expressions and all.
4)Go on strike,stop doing activities with her,don't talk to her. Tell her your on strike untill she stops.
Hope I helped,I know I not to good at this but smoking sucks and i had to answer this