I have been learning new habits continuously, particularly as I've been implementing a full GTD system - not my half-@@@ system - in the last almost half a year now. The best way for me to get into a new habit is to have a daily checklist. On it, and this is no joke, I actually have "check tickler", because this is a new thing I implemented and I found myself forgetting the files. I now use it for most new habits, as well as to make certain I do my workout at least 3 times a week.
There are 8 columns next to the actions, one for each day, and a sum column where I add up the totals for those things that need totaling (example: workout total is 3 or three checkmarks). I then change this daily checklist during my weekly review, adding or removing habits I feel I need to remember.
PS The only reason workout is there is because I really need to get back into a regular routine. I also don't adhere too well to any appointments I make with myself, so I prefer the "openness" of this.
I started using this exact same method about 3 weeks ago after reading a book called 'Vital Factors' - which basically talked about setting clear targets for a week in a transparent kind of way and then using an accountability tool to check against progress. It's really working effectively for me in setting up different habits in several different areas of my life. And yes, things like check tickler are on there for me too in terms of my GTD implementation, along with get inbox to zero once during the day.