
I start off by feeding them in there so it is a pleasant experience, leave the door open initially and then gradually close the door for longer periods.
Never take them out if they are making a racket and jumping about, speak softly till they go quiet for a few seconds, praise them and let them out.
Drape a blanket over to make it like a den, put a T shirt/item of your clothing[no buttons or zips]you have been wearing in with the bedding so your scent is present when you are not.
I have never had a problem crate training even an adult, it is never a place of punishment and a chew is given if they are being crated because I am going out.