1) Assiduously 2) Attentively 3) In a diligent manner 4) Industriously 5) Meticulously 6) Painstakingly 7) Tirelessly 8) With diligence 1) Busily 2) Laboriously 3) Untiringly 
• (adv.) In a diligent manner; not carelessly; not negligently; with industry or assiduity.
Dil'i·gent·ly adverb In a diligent manner; not carelessly; not negligently; with industry or assiduity. « Ye diligently keep commandments of the Lord your God.» Deut. vi. 17. 
[adv] - with diligence
diligently A description of something that is done in a careful and detailed way.
adverb with diligence; in a diligent manner; `we may diligently observe the Lord`s supper on the first day of the week, diligently preach the gospel, or minister to the saint`
in a hard-working manner