spinnaker:
Read what they say carefully. Don't be afraid to seek independent advice, particularly if they want your signature for something.
Sadly, the other thing to remember is to look after your own interests, because no one else is likely to do it for you. Especially ask for legal advice if you're asked to sign anything - you don't have to agree to anything in order to get the statutory minimum payout. That's where a decent union rep can help out, getting the appropriate qualified advice out to people.
Don't forget networking - friends and colleagues from past jobs may have the inside track on suitable vacancies with their current employers. Make sure they know you're looking.