• Basic forms
• 努める — to make an effort; to strive / base form
• 努めます — make an effort; strive / masu form
• 努めた — made an effort / ta form
• 努めて — strive and …; make an effort / te-form
• 努めない — do not strive / negative
• 努めれば — if (you) make an effort / conditional
• 努めろ・努めよ — make an effort! / imperative
• Other common forms
• 努力に努める — to make efforts
• 改善に努める — strive for improvement
• 成功に努める — work toward success
• More
• 努めたい — want to make an effort / 〜たい form
• 努められる — can make an effort / potential
• 努めなかった — didn’t try / past negative
• 努めている — is striving; is making efforts / progressive

努める（つとめる） is an ichidan verb. Drop る to add endings such as ます, た, て, ない. It expresses conscious effort toward a goal, often used in formal or written contexts, as in 改善に努める (to strive for improvement).