Tsui, first of all, you should try to relax. Stress can delay your ovulation so it is best to relax. I know it is hard but try not to think about it too much. Second, I think you can start taking your basal body temperature every day. Do it at the same time every morning and before you even get out of bed. Record your temperature (you can download a very good temperature chart from www.tcoyf.com) and try to pay attention to any shift of temperature. Since when your temperature rises 2/10 of a degree can mean that you have already ovulated. So what you should do is to observe your cervical fluid everyday as well. Usually, our body will generate "egg white" like cervical fluid before our ovulation. If you notice that your cervical fluid is very strechy and wattery, it is the best time for you to have sex. You should keep trying until you see your body temperature rises which means you have already ovulated. There are a lot of tricks you can do to increase the chance. For example using the ovulation prediction kit but it is always best to use together with your measurement of temperature and observation of your cervical fluid.
I found a book which is recommended by a lot of women called "Taking Charge of Your Fertility" by Toni Weschler, MPH which has all the details about how you can better understand your cycle to achieve pregnancy and birth control. I think it is a very good book. My husband and I want to have a baby as well, we have been trying for months. Since I just got off from pills, my cycle is very hard to predict. Then I read the book and started to take my temperature everyday. Eventually I understand my cycle better and after trying one month after I read the book, I got pregnant! (but too bad that I have a miscarriage shortly after that) So I think you can try to get the book and read it.
I wish you all the best and hope that very soon, we all can have a healthy baby. :)