There are a lot of efficient techniques from CTAB modification to different kits like Qiagen etc. What will be the best depend on what quantity and purity of DNA you need and how much money you plan to spend for this.
Use the general CTAB method. You can find the protocol in this paper by Kooistra et al 2003 (http://onlinelibrary.wiley.com/doi/10.1046/j.1529-8817.2003.02083.x/pdf). Instead of filters I directly spin the cells and continue with the CTAB extraction. The quality is variable, but if you are looking for PCR analysis, this produces enough DNA for you.