Since you can combine various loadouts for Pilots, loadouts for Titans, and Titan classes, you have a lot of choices. Here are three specific possibilities, if you would rather go with something tested rather than experiment on your own.
Use the Rifleman Pilot loadout, the Stryder Titan, and the Artillery Titan loadout.
You will have a lot of speed and the ability to perform powerful long-range attacks, although your defense will be lower. Fight from a distance with the Rifleman and Artillery, and use the Stryder’s speed to avoid attacks.
Use the Assassin Pilot loadout, the Atlas Titan, and the Assault Titan loadout.
You will be in the middle of the road, with the ability to deal damage, protect allies, launch quick attacks, etc. all moderately well. Vary between roles to help your teammates, rather than focusing on a specific aspect of combat.
Use the CQB Pilot loadout, the Ogre Titan, and the Tank Titan loadout.
You will have high physical resistance, strong close-range attacks and parkour abilities, and the ability to absorb and return enemy fire. Shield your allies by taking damage for them and beat down any opponents that get too close.
[more cheats for Titanfall here]