Days Best for Getting Pregnant
If the menstrual cycles are regular, then it is somewhat possible to predict when ovulation (eggs from ovary coming out) will occur in next cycle.
Each menstrual cycle can be divided into two parts, one that occurs before ovulation and the other that occurs after ovulation. The period after ovulation is relatively fixed and it is 14 days.
For example, if the cycle is regular and is of 30 day cycle, then the 16th from the date of first menses is going to be the day of ovulation. So, having sex on 15, 16 and 17th day after first menstrual bleeding will have the highest chances.
The body temperature rises by half degree Farhenheit when ovulation occurs. So if a woman measures her body temperature every morning just after getting up from bed, then she may find out whether she had ovulation. The problem with this methods is that if fever occurs or if the temperature is not measured correctly, then one can miss it.
There are ovulation kits available (not sure whether they are available in Pakistan) which can be used to detect whether ovulation occurred. These tests can be done at home from few days before the expected ovulation day to few days latter.
Hope this helps