From my experience you need to work out your own carb to insulin ratio, how many units of insulin to take is critical as too much can either send you into hypo or be retained within your body increasing insulin sensitivity and converting more glucose into fat. It can be a bit hit and miss until you manage to work it all out, and it is really messy having to calculate how amny carbs are in what food before a meal. However a good rule of thumb for me appears to be approx 100g bread, pasta, potatoes and rice will all add about 60-70 carbs to a meal. Fresh veg and some fruit will keep your carb down to around 10-20 carbs per meal. I am currently working on 6 carbs to one unit of insulin. You will need to test before a meal, work out how many carbs you are eating and then decide on how much insulin to take, (most nurses reccomend you start at 10:1), and then take another reading after 2/3 hours. If you have gone below 7 then you are pretty much there, if not you may have to adjust your dosage until you get it right. If you go too low then increase your dosage to get between 4.5 and 6.5. Oops this is for those on basal and rapid insulin, I don't think the same principles work for the mixed insulin as it is expected to work throughour the day, however I would be expecting to acheive a fasting level of under 7 in the morning.
Hope this helps