Some kids get potty trained very fast and early and others may take a very long time. According to the American Academy of Pediatrics, "most children start to show interest between the ages of 18 months and 24 months and some children are not ready until they are 2 1/2 years old". "As a general rule of thumb, children are developmentally ready to use the potty around the age of 3. However, remember that children develop at different rates and that not all children are ready at the age of 3." says Tanya Remer Altmann, M.D., FAAP, editor-in-chief of the book, The Wonder Years: Helping your Baby and Young Child Successfully Negotiate The Major Developmental Milestones.
Before we started the process, I took my daughter with me to the store to buy a new potty and told her that it was a very special potty only used by big girls. She was very happy and proud of herself. She knew that she was going to use the potty and was no longer a baby.
In addition to the new potty I also bought her "Elmo's Potty Time" DVD which WE absolutely love. It is very educational and encouraging with a lot of cute songs. It discusses diapers, training pants, kids underwear, having accidents (it is ok), wiping, flushing and washing up, all in a very gentle and fun way. It also mentions that it takes time and requires lots of practice. At the end, all characters and actors sing together a nice song that makes you sing along saying that everybody goes: mothers, fathers, grandparents, sisters, brothers, doctors, teachers,... and that they do it every day. Very, very cute. I recommend it!
I believe that the key for a successful potty training process is to be consistent and patient and if you get frustrated (which is normal), try not to show it!
Note: I haven't received any monetary compensation to write this post. It is my personal experience and opinion.