Keep the whole thing casual and low key. Learning to use the toilet is not a big deal that requires gold star charts and large rewards. It's just a handy skill that kids acquire in the process of growing up. Once they have it mastered, it opens up some nice opportunities for them -- similar to the way that riding a bike or learning to read expands their world.
And just like two-wheel balancing and reading, we cannot force the acquisition of this skill by doling out rewards or punishments -- the child's body and nervous system simply must be sufficiently developed before they can master it.
Since each child's physical development has its own timetable, there's no point in pressuring her or comparing her with other children. When she is ready, it will be obvious, and it will happen fairly quickly.
Set up a little potty before you think she's ready to use it, so she gets accustomed to seeing it there. The big toilet can be kind of scary for some kids, whereas others prefer it because it's more 'real'. If she prefers the big toilet, consider getting one of those seats that make the opening smaller so she doesn't fall in. (!)
There are some cute picture books about using the potty these days - read those together just like your other books. Let her see you using the toilet, and mention casually that she will enjoy feeling clean and dry someday when she's ready.
Superabsorbent pull-ups or diapers prevent the natural sensory feedback of wetness on the skin, which can be important information that help kids link cause and effect together. When she asks, let her switch to wearing underwear at home even if she's not quite 100% reliable yet. (but not necessarily in the car or on long outings, where changing clothes is complicated!)
Think of this period as similar to the time when the training wheels come off - they still fall a lot while they put the finishing touches on their two wheel balancing act, but with every fall they learn a bit more about how to stay upright. Every wet incident brings her closer to dryness.
When it's warm outside, consider dressing her in long dresses or T-shirts with no underwear when she's in the yard. This is the quickest way I know of to help them link up the pre-pee-sensation with what comes next.
It's a process, so expect "accidents" and don't make a big deal over rewards or consequences. A quiet word of acknowledgement for staying dry is enough.
Stickers and rewards, for some kids, only increase the stakes on their 'failures'. They not only suffer the physical discomfort of wet pants, but also become upset with their bodies for not cooperating to earn them stars.
When kids' bodies are capable of consistent control, they usually don't need to be bribed to use the potty. Wet pants are pretty uncomfortable, and that's enough natural motivation right there.
As much as possible, stay out of it. Give her control over the process. Show her what you want her to do when she's wet -- including exactly where to find the clean clothes, and where to put the wet ones. I'd recommend that you set aside a special laundry basket for this purpose, because you'll want to be washing that laundry more frequently than the dirty but dry clothes.
The reality is that we cannot control our children's elimination processes. We can, however, help them learn to take good care of their bodies, and make it easy for them to do so. Once that's done, it's time for us to step out of the picture. The more we push and prod and bribe, the more our interference detracts from nature's feedback loop.
If you'd like some additional support and guidance during this process, contact me to schedule a phone or email parenting consultation: email@example.com