Buying my first new car on pcp, what should I be looking out for?

Hi lads

As title says I'm in the market for my first brand new car, always wanted one and finally have enough salary to afford repayments.

Really like the new merc cla and reckon I'll have a look at that.

Question is it will be on pcp is there anu tips or tricks to keep an eye out for.
Never bought from a dealer before and want to get the best deal possible.

Thanks in advance.