There are two ways:
1. Give the Pokemon you want to train an exp. Share. It can be obtained by delivering the letter to Steven and the package to Capt. Stern. Go back to the Devon place in Rustboro and the headmaster will give you an Exp. Share. So anyway, put the Pokemon holding the exp. share in the front of your party. Go in a battle with wild Pokemon/Trainer Pokemon. At the end, the Pokemon will gain double the exp. points. Tip: If you're training for something (Gym battles, Elite four), battle Pokemon of that type (ex. When I was training for the 8th gym leader, I knew he had water type Pokemon so I trained my Groudon underwater). Note: This takes a very long time.
2. Put the Pokemon you want to train in the daycare center. Go to the desert near Lavaridge town. Make sure you have an Acro bike. Use it on the slope. You can't get up, but for each step you take, your Pokemon in the daycare center gains 1 exp. point. Leave it on for a few hours or the whole night. When you're done, you Pokemon should have leveled up. Note: this makes Pokemon less friendly.
levels 55-61
give it to your pokemon, it will raise its Contest condition.
i suggest, just raise your Pokemon
It depends on the pokemon you're asking about. Many evolve at different levels.
Well yes there are, but you have to have the right gameshark. I only know because I got Pokemon ruby from a used game store with the battery dead ( you know in the game cartridge) and hundreds of rare candy , expensive items and money.
The cave of Origin, levels 32-35
you feed it blue and indigo and gold POKeBLOCKS.
The best way to raise your Pokemon in Pokemon Sapphire is to have all 8 Hoenn badges and trade them for Pokemon Ruby version. Doing is will make the Pokemon Ruby Pokemon evolve faster. It works like this because traded Pokemon will gain a boosted amount of experience so they will grow much faster. Example you trade a Rayquaza (Pokemon Sapphire) for a Rayquaza (Pokemon Ruby) at LV 70 once Rayquaza you received from Pokemon Ruby will gain boosted EXP points every time. And the same goes to the Rayquaza that was transfered into Pokemon Ruby. Traded Pokemon grow much faster in trades than normal.
First you might need to raise it up from a pikachu, which can be found in the Pokemon safari near Lilycove.
you cant. the only way to get one is to get a bagon and raise it to a salamance.
your attack will raise by 3 every level, but it reduces your speed
in route 114 in the grass from levels 15-17 and there is a 40% of catching it