My advice is to test lots. I found that was the best way to keep an eye on things and keep tight control.
Also, be prepared for hypos. Although these tend to happen in the early part of pregnancy, it's always wise to watch out for them and have hypo treatments around the house.
My final bit of advice is not to be freaked out at how much your insulin needs may increase in the second half of pregnancy. My basal almost tripled and my ratios were completely different. As someone who is normally very sensitive to insulin, it was quite a shock to have to take much bigger doses.
Best wishes