Your best bet is to get a pair of Fischer lovebirds as young as possible. This will help bond your birds to you faster. As your birds get used to you, try to get them used to other people such as your parents and family members. This will make it easier for them to be handled by other people in the future.
They can also get used to other animals, such as dogs and cats. If you want them to be friendly, feed them from your hands. This will help them to get used to you and let them know that you are not a danger. When you feed Fisher Lovebirds, talk to them, so they will come to know your voice. If your lovebirds are cage aggressive, it is best that you try to make them more comfortable with their cage. Cleaning the cage once a week will help them feel more at home. You can also use a screen cover to cover their cage. You can also try to give them more toys to play with in their cage. The more they stay in the cage, the happier they will be.