My usual gaming group plays Settlers of Catan with two house rules. One is pretty common and one, I think, originated with us; the other is pretty widespread. Both aim for an effect of smoothing over the early game.

Friendly Start: is pretty common. For the first two passes around the table, 7’s are rerolled.

Build Roads Last: When placing your settlements on the board, you place only the settlements, not roads. Then, in the same order the settlements were placed to begin with, the roads are placed. This helps players make their placing decisions faster (no agonizing over what directions are likely to be free) and makes it less likely that a player will be in the frustrating position of wasting an initial road. For this reason, it is very novice-friendly.