To form the present polite form add -masu to the infinitive for the positive and -masen for the negative. For the past polite form add -mashita to the infinitive for the positive and -masen deshita for the negative.

ときどき映画を見ます。
Tokidoki eiga o mimasu.
I sometimes watch movies.

たかはしさんは魚を食べません。
Takahashi san wa sakana o tabemasen.
Ms. Takahashi doesn't eat fish.

毎日漢字の勉強をしましたが、すぐ忘れました。
Mainichi kanji no benkyou o shimashita ga, sugu wasuremashita.
I studied kanji every day, but I soon forgot them.

一時間待ましたが、友達は来ませんでした。
Ichi-jikan machimashita ga, tomodachi wa kimasen deshita.
I waited an hour, but my friend didn't come.