Different people have different opinions and you should find yours. But here are some helpful tips.
If you're the type of person who loves fighting and trying out new techniques search high and low for trainers who want to battle. Also, you can re-battle them by using a device called a 'Battle Seeker' or something like that.
If you're very creative and are hard working and dedicated to what you do try competitions. It's my favourite, personally, because you have to collect and plant berry's to buy accessories. You can find accessories. You talk to people and find them in other places. You can show off and you can dress up your Pokemon! It takes a lot of hard work and effort to be the best though.
If you want to spread Pokemon around the Sinnoh region, give your favourite Pokemon to the Daycare Centre in Solaceon town and receive the eggs to grow up into Pokemon.
Hope it gives you some ideas
the best Pokemon on diamond would be arceus but you can only get that from action replay, other than that i think the best Pokemon would be giritina..
the best Pokemon for the Pokemon league is definetly latios
in Pokemon diamond it is in were the elitle four thing is outside in the water. and that route after it were shaymin is. but you have to use a rod.
Chimchar
swampert miltic
The best thing to do is turn your DS of, its the only thing you can do
There is no Pokemon temple! There is such thing as Pokemon diamond.
a red tent
It is no such thing as the moonbay in Pokemon diamond.
There's no such thing as alamos on Pokemon diamond.
no such thing as fania on diamond
no such thing
Diamond is not a Pokemon but i think Arceus is one of the strongest Pokemon ever.
That its Pokemon because Pokemon is cool and the adventure feels really like being a real trainer but on a DS/DSi.
the best Pokemon on diamond would be arceus but you can only get that from action replay, other than that i think the best Pokemon would be giritina..
there isn't such a thing
There is no such thing as them.