Run them ragged during the day. Lots of walks trips to the park and develope a bedtime routine and dont stray from it. Keep taking the child back to bed. It's a contest of wills here and YOUR the adult. DONT give in! Ever!
Well we really never had to have that Problem! Since dd was 4 or 5 months old she has always slept by Herself..in her Crib..Now she is 3 and still sleeps by herself..There has been only 2 times out of her whole life so far she has ever slept with us in our bed! thats about it
I have a consistent night routine-- bath time, brush teeth, story time, bed time, etc. If you have a daughter you can try modeling that behavior with a doll. Our daughter has a couple of favorite toys that she needs to get ready for bed. Maybe get a special bedtime bear they can cuddle with while they are in bed. Good luck!