One of the most powerful ways to make a track sound bigger and more impactful is by doubling it. The quintessential example of this is the doubled rhythm guitar part, which can really fatten the sound of your mix, and help make the stereo image feel nice and wide throughout the song. But it’s not just rhythm guitar. Doubling is also used to great effect on vocals, both lead and backing, and section parts like horns and strings, and, really any part you want to thicken.
A useful way of creating big guitar chords is to play chords without the third note. So for example a C chord consists of the notes C-E-G. Play the C and the G notes and you can add distortion and still double the chords for a smooth sound.
Good point. What you're describing is what's commonly referred to as a "power chord." When recording rock rhythm parts, power chords, are most commonly used. Since they have no major 3rd, they provide a harder-edged sound.