The optimism provides you strong faith, openness to notice the opportunities that come as answers to the prayers and readiness to follow them.
If all your life you have been pessimist you might find difficult to think only positively. No matter how hard it seems you have to change your thinking patterns otherwise you will never experience the fulfillment of your prayers.
This is a problem of free will: either you choose to be loser due to your pessimism, or you decide to think positive in order to reach your life goals. As the only chance to be happy is related with positive thinking be wise and adopt it as soon as possible.
Control very well your mind. Get rid of negative thoughts immediately as they appear. When you have to struggle against your doubts do not pay them attention and focus deeply only on optimistic thoughts.
Never say that something is impossible. If you are really motivated nothing is really unachievable for you.
Negative thinking and speaking is contagious therefore never listen to pessimistic persons who might discourage you. Do not associate with sceptical people because they will sabotage all your actions and prayers.
Get rid of the evil belief that you are damned and that all the bad things happen only to you. If you have the feeling that you are unlucky it is only because of your negative mentality. You may achieve happiness provided you adopt constructive attitudes toward the reality in which you live.
Never believe that God does not want to listen to your prayers. You must be very ignorant and ungrateful if you believe that the divinity has let you down. Actually God answered to all your requests, but many times you failed to recognize it. Just recall all the unexpected help that you received when you were in deep trouble. If you reflect on this sort of events you will be aware how much God loves you and your faith will grow stronger.
Repeat as many times as possible that God loves you till you believe it. You have to be aware of this truth not only with your mind, but also with your heart. Your faith grows stronger if you feel that the divinity takes care of you. When you succeed believing this nothing will prevent to achieve your goals.
Be aware of your good karma by reflecting on your good deeds - it provides you the feeling that you deserve the fulfillment of your prayers. Recall especially your acts of generosity and the moments when you succeeded to express your spiritual love towards your neighbours.
Remind yourself that you are special as often as possible. If you believe it the doubts will never trouble you.