I find the three month timeframe is one that gives me plenty of time to get a 'project' done even with all those other things in life. However it is also sufficiently short that it makes me "get a move on". Another thing that motivates me is sharing the work with others. A promise I only make to me can be constantly postponed but one made to others (say in the form of an agreed time-and-place to sketch a friend) must be enacted.
Last Spring I did a folio of landscapes utilizing my old trick of incorporating a human form into the contours of the scene. All sorts of climates and settings were explored.
Over Summer I was pretty slack but did pen an interconnected set of three fictional tales starting with this one. I am departing from my fantasy and science fiction roots more-and-more and enjoying more realist scenarios.
This Autumn I have worked on life drawing (warning - nudity under the link) and specifically on improving my sketching of faces. I have gotten better but can still improve further.
In Winter I intend to get back to fiction writing and the framework into which I will fit this is Monash Wordfest 2011 which incorporates a short story contest and several seminars. I submitted a short story last year and hope to this year too. I cannot say what that story will be yet but possibly the seminars will inspire me.