I have a few tricks.
First, you could do it the old way. Find an area with Pokemon the same level as yours, then just train there.
Or, you could find out the places with Pokemon that are weak against your type. For example, if you're training a grass type, go fish or surf and battle against water type.
But the way I do it, you'll need a VERY strong Pokemon, like level 60 or higher. Then take the one you want to level up and give it an Exp. Share. It's an item you get somewhere, but I forgot where I got it. Anyway, give it the Exp. Share and take your strong Pokemon to a place where other strong Pokemon are, like I do Victory Road. When you battle with the strong one, the Pokemon holding the Exp. Share will get half of the exp. points you get, which can be a LOT, and it doesn't even have to battle.
Good luck, I hope I helped.
yes
You can find that at codejunkies.com
U Level it up of course
Make a Golbat level up on a high friendship level.
No but if you email codejunkies.com they will make it for you.
Fighting pokemons with almost the same level.
you have to give it a fire stone. If you mean faster then a fire stone, there is no possible way.
No, you can't make new Pokemon on Pokemon diamond...
Well after you get the national dex you can get a Pokemon radar and use it to make patches of grass move.If the patch is colorful then its a shiny Pokemon
NO. There is not. That would be cool if hey do
Since your Pokemon gain exp for each step you take, making your character take more steps than normal (like, ride a bike or something) will make your Pokemon level up faster.
01FFF3CF This code actually makes all wild Pokemon level 225, but they level back down to 100 after one battle.