I start out the game only training the pokemon that I plan to use later plus the ones that I need to beat the first few gyms. Then as I find pokemon that I plan to use in the future, I add them to my team and train them until they get caught up.

So far it seems to be working as I just creamed Erika with my on the first time in the gym, not even leaving before battling Erika.

i raise my pokemon evenly but i tend to raise my starter a couple maybe 5 levels for just because i depend on my starter so much

I always evenly train my Pokemon just to make sure that I dont lose

I train them evenly. If my starter starts to pull away, I smack myself on the head and restart. After the E4, though, it's a completely different story.

Right now, even though it's Emerald, I'm training just my Mudkip throughout the game until after the E4.

In FR/LG I trained them evenly, but I might start over in LG and go with Bulbasaur throughout the entire game - seeing as I've never chosen the Grass starter and stuck with it through the game...

I chuck my starter at level 45 because i often ruin them. I then take the ledgendary birds a strong dragon type (gyrados or Dragonite my best is Salamence lvl80) a mewtwo and my fave pokemon at the moment and time.i.e. one day armaldo one day heracross. They then gradually even themselves out except for some reason my zapdos soared to lvl80, very odd!!

Actually, until Elite Four, I usually train only one pokemon, the starter. I have tough times on maybe on gym leader, and that only prompts me to level up about 5 levels and return to destroy the gym leader, and that pokemon is all I need, along with legendaries available, to easily defeat Elite Four. In Fire Red, for example, I had a level 65 or so Charizard and the three legendary birds - somewhat simple victory. A more prominent one was in Diamond (yes, I'm fast ), where I had the Water/Steel Penguin pokemon at level 72 and I challenged the Elite Four, having Dialga and 2 of the other legendaries in my party. I EASILY annihilated the level 58-62's Elite Four Pokemon, and the only one that I stumbled on, though I didn't even need to restart, was the Champion's Lucario - it's a two hit kills me pokemon, so I used a legendary psychic to put him to sleep and obliterated with Hydra Pump.

However, while preparing for Diamond, I was also restarting my Sapphire (I was on a break from pokemon, lost most of my games, so had to start over from Fire Red and Sapphire), and I trained my main pokemon and an Aron. I agree it was easier, and Lairon saved me against the flame gym leader (I stupidly chose grass for starter), and nothing else would've been much of a problem. It's nice, but it takes more time, and I'm better equipped to make an ultimate pokemon after I beat elite four - as in Bred. If I'm going to breed the pokemon to make a better version anyway, why train it?

To each his own, I guess. In FR/LG, though, I must admit, I couldn't have easily, if at all, won without the legendary birds. Lance's fossil-dragon-flying pokemon (forgot the name) has Ancient Power, and I think it kills in one hit my charizard, because of double effectiveness. I needed to use Zapdos against it.

Evenly: I get , like, 10 Levels ahead of the other in-game trainers, which takes away any chance of the game actually being challenging.

Lol... So, I'm contradicting my own stated strategy right now, in LG. I started with Bulbasaur, and planned out my team in advance. Unfortunately, most of them aren't catchable until later in the game, so right now I have a Lv. 38 , and several Lv 10 or less pokemon, namely my two HM slaves, with 3 badges.

I stick with my strategy of leveling one.
So: I have level 45 kyogre, 47 aggron, 48 grass-starter-thing in sapphire. I challenge Elite Four. One of most challenging series of battles ever - fighting a trainer with twice my number of good pokemon and each being 10 levels above. I never had this problem when I only trained one; With a level 60 starter, I could've eliminated without having to rely on Kyogre so much.

I perfer to train all of mine evenly.
Back when I was younger, I always trained only 1 strong pokemon and the rest were weak. It turns out that it can really kill you in the long run (I was never able to make it past my rival in Pokémon Yellow because of that).
So now that I'm older and (somewhat) wiser, I take the extra time to train all of my party pokémon evenly to a nice level. That way, you have less chances of loosing due to type disadvantages because you can switch out and still have a chance.

for the first fight i train all evenly to atleast lvl 50 or sometmes 60-100 depending on how much you watn to crush them or have a good meaningful fight. i generally like to have a fight instead of an OHK fest

Considering these responses, this deserves to move to general dicussion. That way its not off topic speaking about Pearl and diamond ect.
Do us all a favore and move this.

I usually train at a decent even rate. For example, One level 50, 4 level 45's, and one HM slave. That isn't my current team (Far past that now), but it was just an example for the rate of level differences. However it usually turns out I get some less commonly used pokemon high level before my starter. For example, I got a Shedinja and Zangoose to level 100 when my Blaziken was only like 90 in Ruby.

I always level mine evenly, the way I see it, if you have them all evenly levelled you'll have a better chance of winning if one gets KO'd. Most of my strategy is based around type advantage/disadvantage so I need to keep them all at a fairly high level for it to work well enough [my 1-hit KO method]