Visit and read through https://lockthecock.com and make a list of things that you should never mention to your girlfriend.
How many times have you got laid?
Never let your girlfriend know about the number of times that you have got laid. She does not want to make an impression that you have slept with so many girls.
You may be drawing a huge amount of salary but your girlfriend may not want to know about that. There is nothing that should keep you bragging about it. Try to be down to earth.
Do you watch porn?
No one is interested in such matters and especially not your girlfriend. I am sure she is going to get pissed off it if you start this conversation about the number of porn CDs that you have.
You can go ahead and tell about who all are there is your family but no one wants to know about the intricate details about your family. So keep it less and do not get into details about your family.
Your girlfriend does not need to know about your ex-girlfriend and the details about her. It is not even important that you even mention about her.
You may have some great sexual fantasies but no one wants to know about it. So keep your sexual fantasies to yourself and do not mention about it to your date.
Make sure that you do not disclose everything to your girlfriend and keep a control on what you want to tell her and what not to tell her. This is going to make a good impression on her and she will value it that you are not using her just to let out your thoughts and feelings. You want to make her feel special so do not use her as a dustbin to throw all your garbage on her.