What specifically is the problem and what are you looking for it to become?
As someone stated, unles a lovebird is handled frequently from hatching, it will usually not become a sweet little bird.
There are some things you can do though.
1. DO NOT GIVE IT A MIRROR, this will make it more aggressive and loud, especially if it is a sexually mature male.
2. Take it to a Vet and have its wings and nails trimmed, if it cannot fly it will rely on you to for mobility (if you have cats this may not be a good idea FYI).
3. Stick train the bird, and have a seperate area for playtime (find a nice playgym for it). The cage is a area to be protected for most birds and if you stick your hand in the cage you will most likely get bitten, teach the bird to step on a perch with the command "up", remove from cage to playgym (preferably in room seperate from cage).
4. Lots of good toys, with rope, leather and beads and stuff to chew on, they make tons and tons of good bird toys these days.
5. There should be a very good schedule for the bird, wake up at the same time, breakfast at the same time, playtime out of cage at the same time, nap, dinner, and bedtime, a schedule will be very very helpful for cutting down bad behavior.
6. it should have a good balanced diet of pellets and fresh fruits and veggies, feed fruit and veggies in a seperate dish in the morning and evening and have pellets available all
day long. NO SEED, seeds are bad bad bad for birds.
7. have a cage cover it the bird is being too loud cover it up, and you can use the cover for bedtime also, but be aware that they are birds and it is normal for a bird to vocalize, especially in the morning and the evenings.
Those are my suggestions from about 20yrs of keeping birds and 5 yrs of being a zookeeper working with birds.