PAR is the number of stokes a player should take to complete a round with good performance. Click and hold Strike button in order to select stroke power.
Dating sims such as Tokimeki Memorial, and some role-playing games with similar relationship based mechanics to the genre such as Persona, often give choices that have a different number of associated "mood points" which influence a player character's relationship and future conversations with a non-player character.
There are also GL games, which focus on female/female relationships, and BL Games, which focus on male/male pairings.
There are many variations on this theme: high-school romances are the most common, but a dating sim may also take place in a fantasy setting and involve such challenges as defending one's girl from monsters.
The most common objective of dating sims is to date, usually choosing from among several characters, and to achieve a romantic relationship.
The term "dating sim" is also often used incorrectly in English as a generic term for romance-driven games (ren'ai games), a subject matter which is stereotypically associated with the visual novel genre.