If you have chemically treated hair you want to constantly replenish oils with deep conditioners that contain shea butter, olive or almond oils at least three times a week to avoid breakage.
Heat styling is a must if hair has been chemically relaxed, but don't overdo it since your hair is fragile. Only iron what is absolutely necessary, like face-framing strands.
Spritz hair with a moisturizing shine spray for heavy-duty gleam.