Hey Will, I have just started trying to up my breathhold too and have found for static, i downloaded an app on my android phone called Static Apnea Trainer, some basic instructions on how to use it can be found here
http://freedivingexplained.blogspot.com ... ables.html Like they mention, make sure you take it slow and know your limits, only making gradual increases when your ready. I have also started doing Cardio training (Circuit at high intensity and also slow runs where i hold my breath between every second powerpole,tree etc) so far i have gone from 2 mins static to comfortably doing 2.40 and im hoping to increase it further over the next weeks with daily training. Hope this helps and i am not super experienced at freediving so i may not be 100% but there's my two cents.