As much as possible; as far as one can; wherever practicable (used to request or advise doing something to the greatest extent feasible).
なるべく早く返事をください。
Please reply as soon as possible.
健康のために、なるべく毎日歩くようにしている。
For my health, I try to walk every day as much as possible.
なるべく予算内で収めたい。
I want to keep it within the budget as much as possible.