one way of doing it is to work backwards. sounds mad, but here's the technique. it's a sort of creative visualisation thing - works for me, so i thought i'd share it.
an awful lot of the time, working out the first step is the hardest - "where do i start?" - and then "what do i do next?". start with imagining yourself having achieved your goal - in detail. then go to what you had to do to get [/i]there[/i] - the day before, for example. then the day before that, etc., etc.
a simple example: "i want to eat chocolate cake". imagine yourself eating it. what did you do before? cut a piece and put it on a plate. so, you need a knife and a plate, and a cake. before that, you had to take it out of the wrapping (sounds daft, but bear with me). before that, getting in from buying it (i'd mkae it myself, but that's a different story); before that, actually buying it - imagine yourself at the shop paying for it (you have to remember money). before that, choosing it, and then, in reverse order... getting to the shop, leaving the house, getting ready to go out.
might sound silly, but it also means you get all the preparation you need - knife, plate, money, coat if it's cold, car keys/walking shoes, etc.
hope that's helpful. if it's confusing, ask me about it.