How do you ask a girl out if she has a bf?

normally if you tried to get a girl who was already dating a guy then you would be shot outta luck because she may have strong feelings for thr guy and may not think of you as something close to a boyfriend. one thing get them to break up and make sure you don't get caught. so lets say you are in hihg school with her and you realy want her badly and can't wait till she breaks up with the guy. so you right fake notes and put them in her locker so that she will start to dislike the guy but that may not be enough so do that for about a week(also try to copy his hand writing exactly so she will think it is his and not someone elses) after call her and try to imitate his vocie and make her hate him more then after if this pushes her over the head with him them you can make you move by doing the exact same thing. except right little poems and call her to see if she is okay and ask her if you could take her out but as a friend and then on the friend date if she accepts. try to put your all into impressing you because now she is on the rebound and may not know what went wrong and may think any guy is better then her past boyfriend so do your best to be funny a gentlman and polite as well. then after a little while ask her to go to the next step with you and then you may get her but if not then keep on tring and you will eventually get her.