Barriers to entry – There must be barrier to entry in the
market, either by bond or anything so that no other firms can enter
into the market.
No close substitute – The product a monopoly firms sell must
not have any close substitute because if there is one, then as soon
as the price of the product will increase people will shift to its
substitute.
Number of competititors –The number of competitors must be very
small due to very high cost of production or due to technological
differences.
Advertisement and product differentiation – The firm must
advertise its product in such a way, that the product must look
completely different and unique . With the ability of capturing the
eyes of lots of customers.