Having observed a good number of cross wind landings in the sim and a/c I will offer my 2 pence worth.
Firstly, the simulator is generally a little less forgiving than the a/c, don't get too disheartended if the sim lands firmly.
I have traditionally, due to previous types used the crab technique until the flare. This works OK on the triple, but with only a little practice the wing down works better.
If the opportunity presents itself on your next sim cx, set the sim up to autoland in about 30kts across. The aircraft will start to decrab fairly early, a bit before most pilots who are advocates of this technique would do. At about 75r drop out the A/P and do your best to freeze the controls where they are. Flare slightly earlier than for a normal approach (the a/c is cross controlled and less efficient).
Once that works out OK, try pushing back the point at which the A/P is disconnected, once that works, start increasing the cross wind up to 40 kts.
You now know how to do the wing down in a 777!
Be aware though that the Boeing manual contains an advisory note that pure wing down above 34kts (I think, dont have the book to hand) results in degraded ground clearance. The is also a graph that shows what you will dink depending on bank/pich angle.
Practically speaking, most folks I have watched do use a mix of both techniques in strong crosswinds