Ho Orinoco,I used to be a recruitment consultant and helped rewrite loads of CVs, so I hope this helps:
The basic format we advised was - 1)personal details, 2)employment, 3)education, 4)interests. Last/latest job top of the employment section, and list main responsibilities in a bullet point format. The further back you go the less detail you need to include for each job (I'm assuming as it's 4 pages you've done more than 2 jobs!) and anything that isn't in your career path, (ie that stint as an underwater basket weaver?!) include, but don't expand on - the fewer gaps in your CV, the better.
Reduce education to minimum, ie don't bother listing all GCSEs (O' levels to "oldies" like me!), just put "x GCSEs (including English & Mathematics)". always include the school/college or wherever it was you got the qualification.
Depending on what sort of job you are looking for you could also have a "Profile" section, between personal details and employment. This is where you can big yourself up. always write it in third person, ie "X is an dedicated brain surgeon with 10 years experience within the rocket science sector. Now looking for a managerial role within Hollywood, where her skills and expertise can be fully utilised". Only write about three or four sentences though.
Don't list loads of interests -just two or three, and NEVER put socialising - everyone does it!!
Also add "References - supplied on request" at the end. They should always notify you anyway if they want to take up references, and it saves having to constantly update that bit.
At the end of the day, depending on the amount of experience and how long you have been working, it's usually better to go slightly over two pages than cut out really important or impressive stuff.
Hope that helps!