Use humanity or the human race instead of man or mankind when you are referring to all people.
If you are speaking of a single hypothetical individual, use person instead of man.
Use genderless titles whenever possible, such as flight attendant instead of stewardess, firefighter instead of fireman, and homemaker instead of housewife. Avoid adding gender markers to genderless titles, such as male nurse; use the genderless title alone (i.e., nurse).
Rework sentences in the plural to avoid gendered pronouns and possessive adjectives. This will create smoother and more grammatically correct prose than using a plural pronoun with a singular subject. (Sexist: Each student makes up his own schedule. Grammatically incorrect: Each student makes up their own schedule. Gender-neutral and grammatically correct: Students make up their own schedules.)
When it is not possible to recast sentences in the plural, use he or she or his or her to be inclusive. (The winning contestant must claim his or her prize by Tuesday.) However, using this formulation too often can break up the flow of your writing, so use it sparingly.