IF she is staying dry for several hours at a time, then she is likely ready. It is a skill, and she needs practice. You can spread this out, or get in massed practice......there is a terrific book called "how to potty train your child in one day" by Richard Foxx. You can look for the book, but the basic idea is:
1. YOU must be willing to devote the day to potty training. YOU are the most important link here.
2. She needs lots and lots of practice. So give her lots and lots of fluids, if you know what I mean.
3. Strip her down to her shirt and panties. Have lots of panties on hand. DO NOT use training pants or pull ups. You WANT her to feel wet and the pee running down her leg (its icky and gross- that's the point!).
4. Practice "running to the potty" from where ever she will be eating, playing, etc. (NOT napping, that is too much yet). Might pick a location to stick to that has washable floors. Even let her see YOU go. If you "need to go", say it out loud and let her see you "run to the potty" and put YOUR pee in the big girl potty. Be sure and tell her how good and how much like a big girl it makes you feel (hey, you are her best model at this point!).
5. Look for fidgeting, etc. when she is playing. If she is looking like she might have to go, "run to the potty". Make it positive, make it fun. If she goes, terrific, give her a small reward (how about another drink ;>). Also, might make a chart that she can put a sticker on. Let her flush, wash her hands like a big girl...maybe use a special big girl towel to dry her hands. Make a big deal out of the first few times, but PRAISE HER FOR THE BEHAVIOR....don't just say "you are such a good girl", but tell her why! "look at what you did....you felt that you had to go potty, and you hurried to the toilet and you put your pee in the toilet like a big girl". That way she gets the behavior focused on, and it reinforces the behavior, not just her general self esteem (that can come later!).
6. IF she misses, STAY POSITIVE. Say "eh oh, you missed". Ask her if it feels good to have wet panties ("oh yuck, I bet those wet panties don't feel very good, next time we better make sure you put your pee int he potty!").....Have her "clean up" her panties (take them off, put them in the hamper), have her 'clean up the floor", etc (a little adult help here, of course).....the idea is getting across the point that peeing in your panties, down your leg and all over the floor is no fun- but DO NOT YELL or punish....the clean up serves as the correction. THEN.....since she missed, have her practice what to do next time. "Since you missed that time, let's practice what to do for the next time!")..... Run to the potty 5-10 times (again, make it a game). The idea is to practice (it is a little punishing), but you are practicing the correct behavior.
In my pre-professor days I trained hundreds of kids with developmental disabilities using this method- and 4 of my own kids. It will really, really wear you out, but it DOES work. Once she gets the hang of it, she will catch on really quick.
BMs are a little different.....that comes down to predicting when they go and catching those opportunities. A little more difficult to feed them enough to poop all day ;>
When she has the gist of it, do it again the next day, and the next (much less intensity, and you will how she starts to get the hang of it an initiate on her own). The time and intensity is much less the second day, and less the third, and so on.....that first day is what is so exhausting.
Again, the two most important things here are to 1) keep those liquids coming to have lots of opportunity for practice; and 2) keep even mishaps positive. Pretty soon going to the big girl potty and staying dry and not having to stop playing to clean up the mess and getting really cool praise from mom is MUCH more fun than sitting around in wet panties! Might even have a special fancy pair of undies for her to wear when she gets it...because only big girls who know to put their pee in the pot get to wear (insert your special kind of panties here).
Finally.....have a strong cocktail or other beverage for the end of the day. You will need it after getting excited about how much fun running to the potty is 100+ times! Oh, and be sure no other adults witness you doing the happy dance because pee went in the potty, or the neighbors will think you have completely lost it!
Good luck.....and take pictures. We plan on submitting a picture of DD18 sitting on the pot for her HS senior class baby picture DVD! She is naked, except for a pink baseball cap, my flip flops, and she is holding a book upside down....oh, the memories!!!