Before putting the fondant on, put a very very thing layer of jam on the cake to it sticks.

When rolling the fondant out, don't flip it over, keep the back as the back so if it gets a dirty spot or anything it will be on the cake & not visible. Try not to touch the top as it's really easy to dent, when moving it hold it only by the sides & underneath. Also use cornflour on your work surface not icing sugar as it can be lumpy & you want a smooth surface to work on.

To get the right size, use your rolling pin to roughly measure the top & sides of the cake so you know what size to roll out. Make sure it's bigger than the cake so you can chop bits off.

If it's a square cake smooth down the corners first so you don't get puckers in them. If you get any bubbles, just use a clean pin to pop them & smooth it out. Again, try not to touch the top too much or you'll dent it.

Hope that helps, if you need anymore info let me know (I'm doing my 2nd cake decorating course ATM ).