How to layer a Lasagne
I've always done a layer of bechamel, pasta, meat, pasta, meat, pasta, meat, pasta, bechamel, cheeses (mozzarella and parmesan, from bottom to top). If you put the cheese in the middle the liquid in it (especially in the mozzarella) won't evaporate and you will have sloppy lasagne.

The other factor is the liquidity of your sauce - a thicker, meatier sauce is better for lasagne so it keeps its shape.