At the start of a tournament it's better to be tight, we won't risk our entry with marginal
hands. But let's say we're deep enough to 3-bet UTG.
We would 3-bet with hands that have enough
equity, at least 30%. Hands like medium suited connectors 65, 76, 87, 98, T9. They play well postflop and we can easly fold'em.
UTG has a tight range, so if we raise him with KQ, QJ we would be in trouble vs his holding (AK, AQ, KK, QQ)
With low pairs it's more profitable to just call and give
odds to players behind.