Stuff that works:
* Keep in mind that A1c isn't as important as the number and severity of the highs and lows you're having. Make sure your blood sugars are stable before conceiving too.
* Aim for a lower target blood sugar. When pregnant my goal was 80 at all times (first thing, pre-meal, 2 hours post meal). I tested a lot to prevent lows. Low blood sugars are as dangerous to a fetus as high blood sugars.
* Log your bood sugars, food and insulin. It's a pain in the butt, however most people have better control when they log consistently. It also makes you more conscious of food choices. Iphones have the Track 3 diabetes log app that makes it a little more fun.
* Take the time to carb count accurately. Look up what you're eating in the Calorie King book or, again, use Track 3 app to get carb counts. I've carb counted for 20 years and am surprised how often I'm wrong when I guess.
* Use an insulin pump. You'll for sure want a pump when you're pregnant.
* Like others have mentioned, test a lot or use a CGM.
* Eat low carb. Fewer carbs in, the less chance you have of carb counting or dosing insulin wrong. At the very least eat a "boring" diet with a lot of the same foods which you can consistently predict carb counts on.
* Don't eat large, high carb, and/or high fat meals. Makes insulin dosing difficult.
* Avoid having lows. It's easy to over treat and create highs later on. Then you have another low, and another high...
All these are great suggestions and they work, however the only time I've been in really good control was when I was pregnant. In real life it's difficult to take the time and energy to do this stuff day in and day out.