The LP phase of your cycle (from ovulation to menstruation) is thought to be constant for every woman. It differs between different women from 12 to 16 days with the vast majority of woman at 14 days. 95% of all woman will ovulate in that 12 to 16 day window.
Remember that if you want to have sperm ready for when you ovulate (ovulation takes only 15 minutes) you need to have sperm ready and waiting inside you. Sperm can survive for as long as 7 days (unlikely but possible) inside you. Normal healthy sperm in a healthy woman will survive 5 days but the most likely scenario is 3 days. That means that you will have to have regular sex for the few days before you ovulate. After the egg is released and it is not fertilized, it will live for 6 to 10 hours and definitely die withing 24 hours. So you have a chance after ovulation as well.
Also take into consideration that not all sperm and eggs are healthy and even having everything just perfect does not guarantee that the egg will get fertilized. Once the egg is fertilized, it is not guaranteed to implant. Your body will try to prevent a genetically faulty egg from implanting to protect your life and prevent a highly deformed and faulty fetus.
On the position side, any position that will have your partner ejaculate deep inside your vagina and that will give you an orgasm from about 45 seconds before he ejaculates to a few minutes after he ejaculated can be helpful (even if you have to help yourself to a 'happy ending'

). Also watch out for sperm unfriendly lubricant.
It can also help to lift your hips (put a pillow underneath) for 10 to 15 minutes after he ejaculated to keep the ejaculate close to your cervix.
Best of luck!!