Step 1 · The cross
Same white cross as the beginner method, but built on the bottom, and eventually planned completely before you start turning. "The cross can always be done in eight moves or less."
Why on the bottom
If you build it on top, you have to flip the cube afterwards (a slow rotation), and you can't look ahead to your first F2L pair while you finish the cross. Building it on the bottom feels blind at first. Stick with it.
The bottom center still decides the colors: hold white on the bottom, and the side centers tell you where each edge goes (green front → orange right → blue back → red left, going around).
The basics of a bottom cross
From How to Learn the CFOP Speedcubing Method, the first tricks to pick up:
Put it in now, line it up later
Don't line an edge up with its center and then drop it in. Put it straight into the cross wherever it fits, and make sure the pieces are correct relative to each other. Turn the bottom to line everything up at the end.
Move the cross, not the piece
If a piece can drop into the bottom in one move, but its spot isn't there, turn the bottom (D) to bring its spot under it, drop it in, then turn the bottom back.
The 3-move insert
A cross edge on top with white facing sideways would land flipped if you just turned it down. Instead: move it to the side, then bring it in with the front face, then fix the side. R' F R (or the mirror, L F' L'). It's fast enough that it barely feels like 3 moves.
Use it as the last piece. If you're doing it in the middle of the cross, there was probably a better plan.
7 tips for an efficient cross
- Ignore the centers. Solve the cross pieces relative to each other and align once at the end, instead of taking pieces out to re-place them over their centers.
- The 3-move insert (above) for a last piece with white facing sideways.
- Use one piece to insert another. If a cross piece can go in with one move, see if another piece can ride on top of it and go in with that same move. Look for this during inspection. It comes up again and again.
- Don't move the piece, move the cross (above).
- Plan the entire cross during inspection. Then you don't need to look at the cross while doing it, and your eyes are free to find the first F2L pair. That kills the pause between cross and F2L.
- Watch example solves from fast cubers. You won't remember specific crosses (you'll never get the same one twice). What you pick up is the ideas they use.
- Practice a few minutes per day. Scramble, plan, see how few moves you can do it in. The trainer below shows you the shortest possible answer to compare against.
Your cross should take roughly 10% of your solve time: about 1 second at a 10-second average, about 2 seconds at a 20-second average.
Advanced cross ideas
Bad pieces: deal with them first
A bad cross piece is one that can't go into the cross in one move. Handle them early, not at the end. The trick: set a bad piece on top of a good piece. When the good one goes in, the bad one becomes good. The worst bad pieces are already attached to the white center but in the wrong spot. "Nudge" them out with a quarter turn as early as possible.
Delay the easy pieces
If a piece is already one move from solved, leave it for last, as long as your other moves don't disturb it. Solving it first takes away your freedom to do the rest efficiently.
The replacement technique
When a cross piece is in the wrong spot relative to the others, don't take it out, align, and put it back. Instead, solve the correct piece directly on top of it. That kicks the wrong one out, and you insert it next. It still works out well even when the kicked-out piece is a bad one.
Finger tricks beat move count
Sometimes more moves is faster. Three quick moves beat two awkward ones, and a cube rotation is slower than a single move. To avoid rotations in the cross, a D + y combination can become a wide move like u. Use it sparingly, it's harder to see.
Turning the cross fast (Cross Boot Camp)
- Choose which side to face. Before you start, imagine doing the cross facing each side and pick the one with the fewest regrips. "Avoid B moves" is a rough rule. The real rule is avoid regrips and avoid cube rotations.
- Good first moves: U or D moves are best, R and L are okay, R2 and L2 less so (a finger has to slip under the cube on a stackmat). Never start with F or B. If your plan starts with F, hold the cube differently so it becomes another move.
- If you must use B, set it up so your hand is already in place:
R B,R' BandR' B'flow well. - No cube rotations in the cross: "there's always a better way to do it."
- Use inspection time fully while learning to plan. J Perm took up to a minute and a half per inspection while learning to plan his first pair. Speed comes later.
Cross trainer
1. Scramble your cube with white on top, green in front:
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2. Flip it with z2 (rotate it 180° like a steering wheel) so white is on the bottom and green stays in front. The 3D cube shows this view, with only the cross pieces colored. Drag it to see the bottom.
3. Plan the whole cross, then reveal the shortest solution and compare.
Other shortest solutions
Solutions are ranked to avoid F/B moves and bad first moves where possible. The trainer only knows the cross, so a solution that sets up your first pair can be better than the shortest one.
Sources: How to Learn the CFOP Speedcubing Method, 7 Tips For An Efficient Cross, Advanced Cross Tutorial, How To Solve the Cross FASTER [Cross Boot Camp], Top 10 Most Common Speedcubing Mistakes.