Improve the bracketed part of the sentence.
Many such mishaps can be avoided if we (are) careful.

The given sentence is a first conditional clause structure:
Principal clause: "Many such mishaps can be avoided" (presents a real/possible future outcome using a modal verb in the present form).

Conditional clause: "if we are careful" (uses the simple present tense to denote a possible condition).

Since the sentence is grammatically correct and meaningful as written, no improvement is required.