As the other said, hard to recommend without giving a thought on what you are interested about.
Having said that, hard to go wrong with one of the following:
-Once in a lifetime (finished)
-Acting Lessons (finished)
-Eternum (unfinished)
-Pale Carnations (unfinished, heavy on the sex aspect if that is what you want)
Personal recommendations (would not start here)
-The House in Fata Morgana (finished, no sex if that is what you want, by far the best in terms of storytelling and characters, not recommended to beginners probably though)
-Steins Gate (finished, no sex)
-Summers gone (unfinished, no sex for now, will have later)
I can tell more later with some idea of what you like.
One simple advise: please specify how much sexual content you prefer. A lot of peoppe here just want to masturbate, so they focus on games with sex content. Others dont mind lack of sex as long as story is good.
There are games that have both, but you would be suprised how many people go to story focused games demanding more sex even if it makes no sense for plot. So adjusting your expectations help a lot.