Unwrap and handle the print gently.
Let it acclimate to your space before framing it. Make sure the place is clean and dry.
Lay it on a flat surface (like a table) and place just enough weight on it to force it to lay flat.
Prolonged exposure to sunlight may cause the print to fade.
Framing properly (by a specialist) and with a good frame will prevent the print from becoming wavy and other damages with time.