i agree with annie0000
my daughter can be a handful for her dad, but good as gold for me, its the way he comes across to her,
forcing and shouting does no good so i wouldnt take the advice to do that!
you need to go to their level and reason with them, yes they need to know whos boss but also need to see why its good for them to do as they are told,
i have a naughty chart for my daughter, and a good chart, she is 7 now but cant see why it wouldnt work for 4yr old
basically if she is naughty or doesnt do as she is told, she gets a cross on the naughty chart, 10 crosses and she gets no pocket money on a friday, or maybe no pudding or sweets - things like that
but to make it even we have a good chart, so we praise her for the good things she does and give her star stickers and she gets a treat when she has 10 but a star also gets taken away if she is naughty!
to be honest she rairly gets crosses anymore, she is 7 and pretty well behaved and loves her treats!!
worth a try
good luck xx