i get inspired in spurts: from tasting smth new in the restaurant (usually a higher-end gourmet one) or reading/watching tv (again usually top chefs or indepth foodie programs, iron chef comes to mind). when i want to duplicate smth i try to find several recipes that appeal to me. i tend to read thru lots of recipes/books/online blogs. but mostly i will cook smth that is not too labor intensive.
i often combine several recipes into one. i tend to be very eclectic with mixing various ethnic spices from all over the world, which some people find 'not appropriate'. to me the only thing not appropriate is when it does not taste great. the more products you tasted/experimented with, the better you understand what goes together or not.
and yes i document - if you want to repeat it , you need to measure spices/condiments. when you have like 10 ingredients in some asian sauce - it's very hard to duplicate the taste unless you measure exactly. that is not to say i don't change sauces, but it's ... add this, then that, then a pinch more... and afterwards i write it down right away. even on a piece of paper, but eventually it goes into my computer food-files. and you need a good pantry with lots of spices/vinegars/sauces/etc.
often i find that in traditional ethnic cousines cooking is very rigid and heavy. so i have to adapt it to my tastes: light, lots of fresh produce, lots of strong tastes, lots of various condiments, spices, salads, low on protein,etc. sort of california type of cooking the way i think about it. so i take a recipe for a stew and turn it into a soup or even salad. salad as being mostly greens fruit/veggie combo but some veggies can be cooked/grilled/baked + some prote/nuts/cheese and dressing.
actually i turn pretty much everything into a salad. like take chinese 'gai choy' - it's sort of a cabbagy mustardy green that chinese always wok. i use it as salad greens -it is much better then mustard greens. and it's not a chinese salad either: baked mexican calabasa with goat cheese prosciutto and walnuts, dressed with old balsamico or pomegranate molasses and EVOO. so it's asian-italian-mex-cali? if i have them, i add chinese garlic chives, else just scallions. since i can't always get gai choy, i do watercress half the time, which is the only subs that combines in a similar way. it took probably 6 tries before everything settled to my taste.