1st, what is ur level, my dear? I ask such question because the book u use to practice should be suitable to your ability --> to get the best result.
2nd, some good books I think that U should use are:
- Step up to IELTS - by: Vanessa Jakeman & Clare Mc Dowell --> suitable for 5.0- 6.0 level
- Action Plan for IELTS - by : Vanessa Jakeman & Clare Mc Dowell --> suitable for 5.0- 6.0 level
- Prepare for IELTS + IELTS preparation - by Insearch - suitable for 5.5-6.5 level
- Cambridge Grammar for IELTS - by Diana Hopkins & Pauline Cullen
(highly recommend) --> suitable for 6.0 - 6.5 level
- Focus on IELTS and Focus on Academic Skills for IELTS
(highly recommend) --> suitable for 6.0 +
- IELTS to success - by Janina Tucker & Eric van Bemmel --> suitable for 6.0 +
- A book for IELTS (reading) and Academic Writing Practice for IELTS by Sam Mc Carter
(highly recommend)--> suitable for 7+ level
- Visuals ( writing task 1) and Essay Writing for English Tests (writing task 2) by Gabi Duigu
- Cambridge IELTS 2 - 7 (skip book 1) ---> highly recommend
3rd, if U have iphone, Ipod touch or Ipad, there is a very good IELTS application that you should use is GraspIELTS by ANTA entertainment --> provide essential words, tips and tricks for score improvement --> very helpful, convenient and easy to use
Finally, good luck!
Hope that help!