Find the stopper first
A socket never catches a marble. For each socket, ask what could stop a marble in that cell: a wall behind it, a block next to it, or another marble. A socket in a corner or against a wall is easy to reach from several sides. A socket in open space needs a block or a marble beside it, and that tells you which direction the last tip must come from.
Use marbles as stoppers
Every tip moves every marble, so marbles in a line stack against each other. That is a tool, not just a nuisance. Park one marble against a wall so the next one stops one cell short of it. When two marbles share a row or column, think about the order they will stack in before you tip.
Work backwards from the finish
All marbles must be home at the same time, so the last tip has to land every marble that is not already resting in its socket. Picture the solved box, then ask which single tip could have produced it and where each marble stood just before. Repeating that once or twice often reveals the whole route.
Read the box before you tip
Shadows fall straight down and each marble has a plumb line, so you can see which floor square it is above and whether a block is underneath. Turn the view when two pieces overlap. A marble’s bands match the rings of its socket, which helps when colours are hard to tell apart.
Climb the levels and chase three stars
Every level is open, so start with Easy and move up when a level stops teaching you anything. Each solve earns up to three stars: three for par with no hints, two for finishing within a few tips of par or at par after a hint, and one for any solve. Undo is free, so you can try a line and take it back without losing a star. Your best stars show in the level picker, which makes it easy to return to a level you only scraped through.
The four Hard levels use a larger 4×4×4 box with more room for marbles to travel. Turn the view often: a marble can hide behind a block or another marble from the default angle.
Spend tips, undo and hints wisely
A tip that moves nothing does not count, so testing a blocked direction is free. Undo is unlimited, so try a line and take it back if it scatters marbles you had placed. Hint lights the wall for a good next tip, and hints used are shown in your result, so save them for when you are stuck.