Here is the basic Ferber plan: The times he gives are examples, btw. He says you can alter them as you see fit.
You can do this for naps and night or just start with night, Ferber says day and night sleep are different and admits the training is harder to implement at nap time, because kiddos go in and out of sleep windows. So he suggests to consider doing nights first and then days once nights are down. I'm not exactly doing Ferber (though I did do it strictly for 5 days), but I am not training at naptime, for now, though they seem to be somewhat improving anyway.
Do your bedtime routine and lay down baby awake. Leave. The following are suggested intervals to go in and check on baby. Your goal is to give baby confidence you will return and check on him, but not necessarily to stop him from crying. Stay in with him for 1-2 minutes max and try not to pick up.
Day 1: 3,5, 10 (all subsequent)
Day 2: 5, 10, 12
Day 3: 10, 12, 15.
You get the picture.
If you sense by the cries baby is starting to settle, do not go in. If baby quiets and then starts back up, start the clock over.
Ferber also admits this won't necessarily have an impact on night wakings (which are our big problem). If they are trained night feeders, he suggests you make a choice: Focus on extinguishing night feedings, or focus on making baby go to sleep on own. Once you have one down move onto the other. If you want to focus on extinguishing night feedings, you can either not feed and comfort however you need to back to sleep, or feed less every day and graduate it that way.
If you have any questions I'll try to look them up for you. Keep us posted!!