Look up mindfulness. "making an effort to relax" is an oxymoron. You cannot do that.

Mindfulness literature would tell you about observing without judgment, just being with you, with yourself, and just the way you are, etc.

Say, just observe your breathing the way it is and stay with your breath. Do not try to breathe more deeply but just observe the way you breathe without WILLING to breathe any differently.

"making an effort" = willing, and that is not the best way to go (plus, it is not possible)

On a completely separate note, if you are watching TV and not paying attention, why don't you turn off the TV?