Take a moment to consider your options before you book another test place. Your score is unlikely to increase unless you make a significant effort to improve your English before resitting the test.
If you answered "No" to any of the questions above, you can find more information about how to prepare here.
Resitting the test after a long break
IELTS is a test of English language proficiency, so you need to work on all skill areas to maintain and improve your English. If there's been a long break since you last sat the test, you will need to be aware that your language skills may not necessarily have improved, even if you have been living in an English-speaking country.
Recent research on international students found that it appeared harder to improve in the productive language skills (speaking and writing) than in the receptive skills (listening and reading). The study found that the least average improvement was in writing*.
This means that even if you did well in the test previously, you will still need to prepare thoroughly, and consider taking an IELTS preparation course as a refresher.
* "Investigating IELTS exit score gains in higher education", Kieran O’Loughlin and Sophie Arkoudis, The University of Melbourne, IELTS: Volume 10: Research Reports 2009