I will post 2 routes, Clinical or PhD.
Clinical:
Need 2:1 or higher.
Get a job as an assistant psychologist (a must). To get this, be either male (as there are a lack of these) or female with past experience in care homes etc - voluntary work also helps.
The course requires research experience, so either get a Masters in research or stats, or do a year as a research assistant too.
Make sure you network. The biggest weight to your application is who is your reference.
You will need 2+ years as an assistant psychologist usually, both in different posts.
PhD:
Either
1) look for a PhD in the press you feel you are qualified to apply for - by qualified I mean you know the topic a little, and have your research skills up to date (so you can answer questions in interview) - also visit the supervisor in advance to make sure it is what you want
2) create a topic, find a supervisor at a uni and then apply for a funding grant
3) do a Masters, then return to 1) or 2).
There are lots of other jobs out there, educational / counselling.. but this is foreign to me.
Out of interest. my route:
graduated 2:1
18 months research assistant
1 year Web Designer in London
1 year Teacher in Taiwan
1 Year Assistant Psychologist - child psychology (NHS)
1 Year Assistant Psychologist - neuro psychology (NHS)
applied for Clinical Psychology - offered placement... declined due to opportunity to study a PhD under one of the top 3 psychiatrists in the UK.
Hope this helps, any more Qs, just ask.
Rad