Calculate how many movement spaces you need before movement. Unnecessarily choosing 10 movements when you don't need it makes it more expensive for you as well as the other player.

Scoring involves how many different types of coal you have shipped and how many different shipping methods you used. Don't concentrate on one colour.

The game expects your lit mines and your unlit mines to be equal in number. You will lose points at the end for imbalance.

If you need carts that aren't on the board, or contracts not on the board, use the space provided to rearrange the queue. There will be other contract options or a cart delivered to you (if you can afford it). Choose which option you want first, then set a numerolgical order for the remainder. If you don't have money to pay for the cart you cannot reset your turn. BGA confirm it's because you have still affected the gameplay by order setting.

You will lose points for coals that you haven't brought to the surface.

Left over money only matters in a tie break situation.