Not all out, just harder than normal. If you have to walk every time you finish a hard cycle, you're going too fast. Again, the importance of this step is frequently underestimated. Do not increase fartlek cycles and total mileage in the same week. If you train consistently, very high.
Consistency is the key.
What we found is that the two biggest causes of runners dropping out or exercising inconsistently were conflicting commitments and injuries. Work and family commitments are a fact of life, and everyone has to juggle them as best they can. All we ask is that each runner look at the answer to question number 2 and honestly assess whether the additional commitment is manageable. As far as injuries, it is not uncommon, especially for beginners, to underestimate the likelihood of such occurrences. We would urge a more realistic and conservative approach, which will almost certainly lead to a more enjoyable experience.