I am a mother of 3 boys so I can give you more detail as to how to potty train boys more so then girls, however it is the same basic concept.
First of all never plan your child to be potty trained by a certain age, it just won't happen like that. If it did, life wouldn't be fun and kids would be very boring I think. Each child has their own personalities and this is what makes them fun and exciting for parents.
I don't recommend starting to potty train a child younger then 2, children just don't have enough control of themselves and most of them are still learning other milestones like walking and talking small words. Once your child reaches the age of two, I would go to your local Walmart or Babies R' Us and decide what type of potty chair you want for your child. There are many different kinds out there, remember though it will only be used for a short while do you don't need an expensive one. A safe one however yes.. you want a safe one.
Once you get it home, lysol it and show your child what it is. Put it in the bathroom so he or she can associate the potty chair with the bathroom, when you refer tto your child using it make sure you use words like going potty is a big boy thing and you're getting to be a big boy now. Little tricks are treats for going, small healthy snacks after wards, or a stickerchart on the bathroom door, each time he or she goes place a sticker, or let them place a sticker on the chart.
Also, have a step stool handy for hand washing along with sanitizer for the potty chair, a little trash can for their paper and what not.
Every 30 minutes ask or remind your child to go potty, if they say they don't have to go or don't want too that is fine. Then every hour say come on we are going to the bathroom now and help your child, teach them how to pull their pants down etc. I highly recommend using easy pants and underwear or pullup pants so that it does not hinder your child from achieving his goals.
Overtime your child will surpass the potty chair and be ready to move on the normal toilet, now this will be challenging, as a lot of children have fears of falling in, or being flushed. Show them it is safe, you can also buy seat inserts to fit their small behinds, and they come in fun colors with different characters on them.
Some tricks to make it fun for children are using those toilet blu things because you can tell them to make the water in toilet green. You know blue and yellow make green~! As for other things for girls I am not sure what to do but for boys there are alot of things. With my boys we used fruit loops, we would toss about 5 of them in the toilet and told them to aim for the rings and sink them, we also let them have contests to see who could pee more or further. Once you get them peeing standing up, the rest of it is a piece of cake.
Please teach your children about not using a lot of paper, overflowing the toilet and hygiene, these are important things.
The last piece of advice I can give and the most important of all is NEVER and I mean NEVER get angry at your child for having an accident. It happens, their bodies are learning how to do things and bladder control is a hard thing to accomplish. Also showing anger can hinder and scare them into stopping all together. Also remember each child is different and one child might be potty trained right at 2 years old while another won't be totally trained until 5.
They all will have accidents - anywhere so be prepared, have extra changes of clothes. wipes, sanitizer and wipes with you everywhere.
Happy Potty Training.