The trick here is not only to avoid all obvious sources of carbohydrate (sweets, bread, spaghetti, rice, potatoes), but also to be careful with your protein intake. If you eat large amounts of meat, eggs and the like, the excess protein will be converted into glucose in your body. Large amounts of protein can also raise your insulin levels somewhat. This compromises optimal ketosis.
High intensity interval training, or HIIT, is a type of training that involves short bursts of high-intensity intervals of exercise combined with lower-intensity intervals. One example is all-out sprinting for 30 seconds between 60-second jogging sessions. One workout would involve five to 10 of those high-intensity cycles. This type of workout is designed to burn large amounts of fat in a short period of time.
Just figure out what works best for your schedule and your lifestyle. Most people wait a while after they wake up to start eating; for me, it's easier to hold off for a few hours in the morning than it is to go, say, from 3 or 4 p.m. until bedtime without eating. Plus, if you work out in the morning before you eat, you get to double-dip on fat burning, since your body will use even more of your stored fat for energy.
Here's something else most people probably don't know: Fidgeting is good for you. It's considered a nonexercise physical activity, and it's an important way to burn energy. You get more health benefits if, in addition to exercising, you are a more fidgety, more active person the rest of the day. This means gesturing while you're talking, tapping your foot, just moving around.