how to evolve pokemon in platinum without having to trade

[Gimme]

How can i evolve pokemon in platinum without having to trade?

[Zidarose]

All the Pokemon in this guide will evolve on their own, once they reach a particular level:
Pokemon Platinum Evolution Levels Guide

The rest of the evolutions can be found here:
Pokemon Evolution 200

Some Pokemon require trading to evolve. There is no way, outside of hacking your game, to get these evolutions without trading them:
Trade:
The first style of evolution in Pokemon that encouraged social behavior or having 2 Gameboys and 2 of the games to get the species. It started simply, just requiring you to send it over to a friend and that would be enough. Now though, an item can be required to trigger the evolution. Be careful as some of these evolutions can only be done once. It is worth noting that a trade-based evolution will follow roughly the same move-gain as its previous form.
Kadabra --> Alakazam
Machoke --> Machamp
Graveller --> Golem
Haunter --> Gengar
Seadra (Dragon Scale) --> Kingdra
Poliwhirl (King’s Rock) --> Politoed
Slowpoke (King’s Rock) --> Slowking
Onix (Metal Coat) --> Steelix
Rhydon (Protector) --> Rhypieror
Syther (Metal Coat) --> Scizor
Electabuzz (Electirizer) --> Electivire
Magmar (Magmarizer) --> Magmortar
Porygon (Upgrade) --> Porygon 2
Porygon 2 (Dubious Disc) --> Porygon-Z
Dusclops (Reaper Cloth) --> Dusknoir
Clamperl (Deepsea Tooth) --> Huntail
Clamperl (Deepsea Scale) --> Gorebyss