As others have said a diary is a must. I'd recommend getting into a routine. For a couple of weeks eat the same amount of carbs for each meal on a day-to-day basis. For example, have 50g porridge for breakfast, have a sandwich and the same piece of fruit for lunch and for dinner have the same amount of pasta or rice with your evening meal. Note that it is important that you count the carbs in everything, not just the starch carbs like break, rice, pasta etc.
You'll soon figure out how much insulin you should have. One unit of fast acting insulin brings most people's levels down by 3mmol/l. So, if on day one before breakfast you start of at 7 mmol/l and 2 hours later you are at 13 mmol/l, then you know that the next day you will need to give yourself 2 extra units. Once you have got your insulin doses sorted, you can then figure out what your insulin:carb ratio is and start having a variety of meal sizes or carb portions.
Testing is a must, it's impossible to control diabetes well without testings. So test before and after ever meal and before bed. The before bed and before breakfast readings tell you if your basal insulin is correct. Before you start playing with your fast acting insulin, you MUST have your basal insulin correct. If it isn't, it's very difficult to figure out your fast acting insulin. To figure out your basal dose, don't eat or inject fast acting insulin around 4 hours before bed as this will influence your readings. Compare your before bed and before breakfast readings. If they change by more than 1.6 mmol/l then you will need to adjust your long acting insulin by 10%.
Finally, if you are afraid of hypos (and I am - I HATE them) then consider reducing the amount of carbohydrate you eat. If you are eating fewer amounts of carbs then you will inject smaller doses of insulin. If you are injecting smaller doses of insulin then any mistakes that you make in calculating your dose will be smaller. For example, if I eat a 100g carb meal, I'll need around 10 units for it. If I misjudge the amount of carbs by by 30% (and hence the amount of inculin by 30%), I'll have 3 extra units of insulin in me. So I'll end up hypo. If I eat a 30g carb meal and misjudge by 30% I'll only have 1 extra unit of insulin in me, so probably won't end up hypo and if I do, it won't be a bad one.
Sorry for the essay - hope it helps!!