Jama masjid metro station on violet line is the nearest metro station. If u want to visit the jama masjid, day time is the best. Depends on the weather conditions, best time varies. In summers, 5 to 7 pm is best whereas 11am to 4 pm in winter. Local market near jama masjid opens around 9 am and opens till 7 pm.
If u want to taste old delhi delicious non vage food, then after 7 pm is the best time.
Huge crowd will always present there to welcome u.