Yes I find that quantity can have an effect too, mainly if the food contains carbohydrates. as the more you eat of it the more carbs you consume. So always check on packets and containers, or look up values for fruit and veggies on the web.
Other things that can affect my readings, particularly the pre meal ones, are stress, feeling poorly, and sometimes the weather, e.g. the very hot spells we've had over the summer!
I try to do a fasting test when I first wake up, but only if I've not eaten for at least 8-9 hours, and I test right before I eat, and usually 2 hours after. The pre-meal test lets me see how big a spike my meal has given me - the smaller the rise, the better. If I've eaten something potentially "naughty" carb wise I will also test about one hour after eating.
The recommendations I use for guiding me are
here
except I work to the after meal/post prandial level for non-diabetics, as I know that I can keep to this even though my pre-meal levels are generally in the higher type 2 range.
I also keep a record of trends (my meter can tell me what they are over 7, 14, 30 and 90 days, and I upload the data to my meter's software, so I can also see more detailed statistics). I do this because I believe that al this data gives me a better knowledge of how I'm doing over time, and this is more important than worrying over the odd high blips - I find this way I'm usually doing better than I think!!
But work out what
you want from your testing, when you think you might need to test, and for what reason. It seems very complicated, but you should be able to get to grips with this with practice.
Robbity
PS SOrry about the essay!