You're screwed because nobody is better than Fedor.
Ok ok, seriously enough. lol.
The basic format of an essay I was taught is to have an introduction for your main argument, 3 supporting points in individual paragraphs and then a conclusion wrapping up your argument. So heres what a basic formula of what I would use.
Introduction: Reel them in to make your audience care why the hell your doing an essay on MMA between fighters they probably haven't heard before, and why it's important to be the best.
Thesis: Here's your argument that Silva is better than Fedor because of *this this and this*
Body 1: Stand Up Skill
Point 1: How Silva Fights in the stand up.
Point 2: How Fedor fights in the stand up.
Point 3: Clarify why Silva is better.
Body 2: On the ground
Points 1-3 rinse recycle repeat.
Body 3: Training Regimen
Point 1: Do some research on what Silva does to prepare for a fight
Point 2: Do some research on what Fedor does to prepare for a fight
Point 3: Connect the simularities but also try to discern why Silvas methods would be better suited against Fedor.
Conclusion: Wrap it up, repeating your main points how Silva is the better fighter because of his stand up, his ground game, his training regimine, ect ect.
And there ya go.