I cleared my ISTQB Foundation level sometimes back and below are some of the tips I can give you:
1. The sample Questions will only give you the feel of the questions. Go thru the 5/6 sets of questions provided above and this will help. Original question sets will be similar but not exactly the same.
2. Go thru the syllabus quite a few times. Many questions will come from there..(see the other post in this section for syllabus pdf)
3. Some questions will come from glossary.(see the other post in this section for Glossary pdf)
4. From Static testing if you can remember the defintions and properties of reviewer, inspector etc you will get quite a few questions.
5. Finally If you study completely the second book,I can assure you that you can clear the exam very easily.
Links for download
Chapter 1: ISEB Foundation Syllabus – Chapter 1
Chpater 2: ISEB Foundation Syllabus – Chapter 2
Chapter 3: ISEB Foundation Syllabus – Chapter 3
Chapter 4: ISEB Foundation Syllabus – Chapter 4
Chapter 5: ISEB Foundation Syllabus – Chapter 5
Chapter 6: ISEB Foundation Syllabus – Chapter 6
The link of sample exams in SQAT: (Register an account in SQAT for Free for practice tests)