I don't know if you have heard about a ovulation calender which tells you about your fertile days of the month, it really helps, it's pretty much the days that your body is most capable of developing a baby in other words the days that it is best to have sexual intercourse for higher chances, it's as simple as you type in your last menstrual period and your cycle length, here's the link:
http://www.babycenter.com/ovulation-calc…
(I Tried this link and it is very accurate, this is how i knew what days i was the most fertile when i was trying to conceive)
But if you have already tried this, then i would tell you to find out more about the positions you can do to during sexual intercourse, sounds funny but believe it or not it has been proven to work, it really depends on what position you do when you are trying to conceive sometimes most of the positions you would try wouldn't work because your cervix isn't close enough, and if i really had to recommend you one is Missionary and right after your partner has came put a pillow under your lower back and try to keep it in there for a good while, it obviously lasts in there for up to 4-5 days.
Also try to maintain a good balanced diet, eat well, rest well.
Good Luck!