What should I keep in mind when introducing a puppy to our 3 year old dog?

We just adopted a dog and our existing 3 year old dog is being such a brat! We are letting her out first, feeding her first, greeting her first, etc. to try and enforce their dominence; however, she has started to gaurd her water bowl, she takes FOREVER to eat her food, and she pulls on the leach constantly.. HELP! How long will this last ?!Thank you !

No one can actually give you a set time to how long this may last... But it may take awhile... I have had to introduce my puppy to my 5.8 year old dog, and it took 5 months for them to finally warm up... It just takes time. Maybe try giving them each separate food and water dishes, and keep them like 10 feet apart, but you stand in between them while they eat; than once they start getting used to that, begin moving the dishes closer together... Until you have the dishes a foot apart, its a really good introducing technique i learned from my long time vet.Good Luck