Tiling dilema! help suggestions, we begun tiling our new en-suit in the extension with big tiles (porcelian)?

as he never has tiled before some started to fall off, hence we had to remove the rest, the nightmare begins again. what is the best way of removing all the tile adhesive easily or is it just one of them things we got to keep persisting getting it off the the scr. tips please in tiling large tiles. thanx