Details: Upon arriving in Tree Hill Rachel flirted with Lucas but she never stated whether or not she was actually attracted to him. Their flirtatious friendship worked in both their favours for some time, as it allowed Lucas to make Brooke jealous (as Brooke was refusing to date him exclusively) and it also allowed Rachel to get under Brooke's skin and to find another way to anger her. Rachel knew, and appreciated, that Lucas was using her and allowed it but after the first basketball game of their senior year, Rachel told Lucas that she was done being part of his plan to make Brooke jealous and the two had very little contact from there on out.
Details: Rachel and Mouth had a complex relationship as they were never officially a couple but both held eachother in extemley high regard. Rachel initally targetted Mouth and befriended him in order to spite Brooke but a relationship eventually developed. However, while Mouth developed real feelings for Rachel her's were more superficial as she was quick to drop Mouth for Cooper and didn't pay him much attention during her crush on Nathan. Rachel brought out the dangerous side in Mouth, which he liked, and this caused him to leave for New Orleans with her after she expelled from school. The two embarked on a near-romantic relationship on this trip until Mouth saw her flirting with some other guys forcing him to realize there would always be other guys with Rachel. Rachel then left leaving Mouth stranded and alone, ending Mouth's crush on her. The two do, however, remain close friends.
Details: Rachel and Cooper met and, setting her sights on him, a seventeen year old Rachel lied about her age saying she was a 26-year-old model. They engaged in a sexual relationship but Rachel started to develop deeper feelings about Cooper. Eventually their affair was exposed after Cooper saw Rachel cheerleading and he immediatly broke up with her. However, a persuasive Rachel seduced him and they slept together even thought he knew how old she was. Rachel grew obsessed with him when he started to distance himself - going to the extremes of punching a mirror and lying to him that she was pregnant. Their argument over her apparent pregnancy caused a car accident also involving Nathan and Haley and, even though both Rachel and Cooper survived, he left Tree Hill, and Rachel, for good after learning she lied about being pregnant.
Details: After the car accident and Cooper's departure from Tree Hill Rachel turned her interests to Nathan (possibly as a consequense of her unresolved feelings for Cooper as she explictly stated that Nathan had Cooper's eyes). Rachel flirted with Nathan and used the car accident to get close to him, even going as far as lying about seeing Keith under the water to give them a connection. Rachel clashed with Haley over her flirtation with Haley but she soon backed off when it was revealed Haley was pregnant. Nathan would later tell her she never stood a chance, even if Haley wasn't pregnant.
Details: After fleeing Tree Hill, Rachel returned to her sordid life and worked as a stripper and prostitute. It was here that she encountered Dan Scott and, after he paid her to spend the night with him, they started to connect. Both deciding to get out of the dark places their lives were in they grew close as they reformed their lives. Rachel became heavily involved in Dan's self-help talk show Scott Free Redemption after their marriage but whether she really wants to help people is questionable as she seems more concerned with the succsess of the show. Rachel's romance with Dan serves her more for convenience than it does for love as it helps them portray the image they need to on the show and offers her all the privalage that Dan's money can provide her. However, after Dan realized that Rachel did not love him he filed for a divorce and, in giving all his wealth away after deciding it was wrong to profit of Keith's death, left Rachel with nothing.