LearnHigher (www.learnhigher.ac.uk/students.htm) is a really useful website that brings together lots of resources created by staff from various UK universities.  There is material on group work, referencing, time management, maths and statistics and lots of other skills.  It's all free and you don't even need to log-in.

The Assignment Survival Kit (http://www.kent.ac.uk/ai/ask/index.php) has been created by the University of Kent to help you with various aspects of preparing for and writing an assignment.  It offers a step-by-step approach, helping you plan what you should be doing by working back from your submission date.  While some of the material is specific to University of Kent students, it's useful for students anywhere.

Student Stories (www.studentstories.co.uk) brings together interviews with and articles by current or recent students in which they talk openly and honestly about their experiences of studying.  There are hundreds of audio clips in which the students talk about a particular aspect of their studies, be it issues around settling in and adjusting to university through to thinking about what to do after graduation.

Destinations (www.surrey.ac.uk/destinations) is an online tool that can help you to identify career options and help you to work towards them.  The site contains videos, audio files and links providing advice on many aspects of career planning and personal development.  The University of Surrey has a license for Destinations, meaning that it is accessible to anyone with a University of Surrey login.  
If you are off campus, you will need to log in remotely before you can use Destinations.

International Students
There are lots of websites specifically for international students studying in the UK.  Some of the most useful are:

• Prepare for Success which helps you get used to UK higher education
• Using English for Academic Purposes has useful information on writing academically in UK higher education
• Dave's ESL Cafe provides free grammar lessons