You can either give it pp ups, rare candies, level it up, or give it the soothe bell but the rare candies work best.
The more you train your poke'mon, the more friendly they will become with you.
If you have a magmar with you on your team that will help.
it takes ten steps for a pokemon to be friendly to you
Put a Pokemon with flame body/magma armor in party and 500 steps
Put on three coats of honey, that's the max and it will work faster, or rarer pokemon.
Keep them in your party and battle after a while they grow friendlier
Making it level up, give it poke blocks, giving it zinc, protein.....etc, but if you make them faint, they'll become unfriendly. A faster way is to let them hold an item called soothe bell, it helps making the Pokemon more friendly
luxuray ball
Luxury balls make it much easier to make a Pokemon friendly with you. Making a Pokemon friendly causes certain types to evolve and increases the power of the move return
The more you train your poke'mon, the more friendly they will become with you.
Lots of training & musicals.
evolution stone
If you want to make your pokémon less friendly, you should battle and let it faint. Another way to make it less friendly quickly is to give it Revival Herb.
You can't make the eggs hatch faster, but you can play Pokemon Crystal Version on the Nintendo 64 with Pokemon Stadium 2 which has an option to increase the gamespeed.
It is a special pokeball that has a catch rate between a pokeball's and a great ball's. If you catch a pokemon with a luxury ball, the pokemon will grow friendly to you much faster than normal. This is good because there are several pokemon that will only evolve if they like you a TON. Some of these are Munchlax, Togepi and Golbat
x speed
Walk with energetic Pokemon Walk with energetic Pokemon