Well SirW my girl is a student, studying computer science/programming, and so spends a lot of her time indoors at a computer. She gets very excited and becomes extremely focused when I send her on a walk outside to a park and she is buzzed for a long time afterwards. I have also found that giving her a lot of simple tasks throughout the day, many things she may already have done herself, are an excellent way of keeping her duty in mind.
I ask my sub what she is thinking of having for lunch and then tell her exactly what to have. I have also begun choosing what meal she cooks for dinner, from a list of her favourites with one new recipe she must try each week. This not only has her thinking of me while she is eating but I have also given her instructions where she must brush her teeth after every meal. Just another little way to keep her thinking of me while she performs everyday tasks. She is enjoying the structure that these small tasks provide. Just telling her the way I want a task completed, washing the dishes is different from how she normally does them, allows a control and a structure to be placed on her life without her radically changing her lifestyle. I find it is quite powerful to envelope these everyday activities under my sphere of influence.
My sub is finding writing her journal an excellent time for focus on me (she kneels at the foot of her bed with the laptop on the bed). I also find that actually choosing a sub's outfit for the day is an excellent, and very easy, way to have them reminded of you all day. If you know your sub's clothes then you can pick an appropriate outfit for her work day (with a little unusual twist that will keep her thinking of you). Getting an inventory of her wardrobe is also an excellent task for a sub, for so many reasons. I have chosen a skirt for my sub to wear during her housework duties, and at no other time. My sub seems to be craving the structure such things bring and as I said before I find that it is the simple little things that are the most powerful.
Something else I have found really useful is to provide a schedule for her housework chores, and setting down specific times and days for her to complete these tasks. This way I know what she is doing at a certain time and that is something I enjoy as well and after the initial schedule is written it is something that requires no further input.
Jason