Take it one step at a time. Which dairy products are you having trouble avoiding? Daiya makes a good rice cheese. So Delicious makes some tasty yoghurts and ice creams out of coconut milk. Tofutti makes a dairy free cream cheese.
But substitutions won't be the same. You really need to start by totally avoiding dairy for awhile. Take it a day at a time. Or a meal if you need to. After you manage one dairy free meal, do you really want to undo your work? You can manage one more...keep telling yourself that. :P It does work.
Meanwhile, focus on meals that are naturally dairy free, and invest in some good guacamole (Trader Joe's has some that's as good as homemade or better!) If you can avoid having dairy in the house, you'll be less tempted to eat it. And if you have acceptable alternatives, you'll hardly miss it. It's hard, but you can do it! (My daughter has been dairy free since she was 8 or so, she reacts to both lactose and casein.)