Taking out a mortgage is a very serious thing, which is why it is important that you do everything properly. One thing that you definitely need to keep an eye out for is lenders who will try to make you buy payment protection insurance. This is a bad idea for several reasons.
Firstly, many ppi policies are wrongly sold this way. This then means that you have to claim for compensation, which you can either do on your own or with the help of a ppi claims company, both of which are huge hassles.
Another thing that you definitely need to look out for is interest rates. A lot of mortgage providers will try to get you to sign up with extortionate interest rates that are going to be very difficult to manage, especially for those who are already in some kind of debt. As long as you do your research then you should be fine.