In Canada GM crops include alfalfa, beet,canola, corn & soy. If you try and avoid processed foods including sweeteners, corn flakes, corn syrup, canola oil and white sugar you're already doing a great job limiting your intake.
Canada imports squash, papaya & vegetable oils which are often GM.
Buying organic takes out the risk, as genetic modification is prohibited for all organic products. By purchasing organic meats you are ensuring you are not eating what the farm animals have (usually GM corn, soy and canola).
Buy cane sugar or organic sugars and corn (ask your farmer what kinds of seeds they plant :)