Unfortunately, there are not any tricks available that will give you any control over how Wurmple evolves. Which evolution the Pokémon morphs into is entirely up to chance, similar to how players have no control over the evolution of Cherubi.

It's likely that if you're looking to achieve both evolutions of the Pokémon you'll have to catch multiple Wurmples and evolve them. It will likely take more than one try for each, so don't pass up on the opportunity to catch a Wurmple when you can.