In Islam, conversation, whether verbally or in writing, between men and women is permissible in and of itself, but it may be a way of falling into the traps of the Satan. Whoever knows that he is somewhat weak, and is afraid that he may fall into the traps of the Shaytan, has to refrain from such conversations, in order to save himself. In any event, please see below for some conditions and guidelines.

It is haram for a man to have a girlfriend and it is haram for a woman to have a boyfriend. The evil consequences and misery caused by such relationships are obvious to anyone who observes real life. For more, see the detailed answer.

Marriage is obligatory for a woman who is unable to feed or clothe herself unless she gets married or she fears falling into immoral acts if she does not marry. What a woman can do to fulfill this obligation is not to refuse marriage when a suitable, compatible man comes with an offer of marriage.

Deliberately looking at a non-Mahram woman and continuing to look after a first accidental glance is prohibited. It is forbidden to look at any part of her body, whether you think she is beautiful or not, whether it provokes sexual desire or not, whether it is accompanied by evil thoughts or not, and whether it leads to immoral deeds or not.

Masturbation (for both men and women) is haram (forbidden) in Islam based on evidence from the Quran and the Sunnah. See the detailed answer for 13 tips on how to give up masturbation.