Please visit a gynecologist and go for follicle study cycle... Lot of women tend to ovulate irregularly.. Like your periods will be regular but ovulation will be irregular. Even I am TTC, I had ovulated on 21st day of cycle which I got to know because I was going for follicle monitoring to my gynecologist.

Aparajitha try on particular dates when chances are high as 90%. Monitor your cycle day 10th to day 15th from your last period is consider as an ovulation period if you try during this success rate is very high. For example if your last period started on 10th then from 20th to 25th will be higher to give positive result. Make relation on alternate days say as 10th day 12th day n 14th day. But don't be pressurised just enjoy your relations. Take a healthy diet. All the best.

if you have been trying for 6 months without success, you should visit a gynecologist....