Descendent (7th) House
This is an indicator of 'Love at first sight' as well as "Opposites attract". Many couples with incompatible Sun Signs might be drawn together because of matching Ascendent-Descendent. For example, a Sun Sign Leo with Gemini Ascendent might be drawn to a Sun Sign Taurus with Sagittarius Ascendent, even though their Sun Signs Square. This is usually a case of instantaneous attraction, but it might not bode well for long-term compatibility, because it is indicative of a dissonance in style but not necessarily of complementary personality traits.
Mars and Venus placements is another indicator of attraction and sometimes compatibility. Mars and Venus are said to represent the inner male and female of the individual respectively, and they will act like their Mars (Male) or Venus (Female) when in love or when approaching the opposite sex. Matching Mars and Venus placement between two parties, will create the illusion that they have found their "dream" or "perfect" lover. For example, Libra Sun with Leo Mars and Scorpio Venus, might act like a Leo with regards to the opposite sex, and looks for a female with Scorpio Sun or Venus. Opposite Mars and Venus placements (i.e. Mars conjunct Venus between two charts) will create strong physical attraction.
Mars- 5th House
Mars represents physical attraction and 5th House represents love. This is a combination where physical attraction triggers romantic feelings. If someone's Mars falls into your 5th House, he or she might seem terribly attractive to you, leading you to idealize them. This aspect is usually not too strong on its own, so it works in conjunction with other favorable aspects to create a sense of attraction.
Mars- 8th House
Mars represents physical attraction and 8th House represents Sex, Death, Rebirth, Control. This is what we call tongue-in-cheek "fatal attraction". If someone's Mars falls into your 8th House, your physical attraction towards them is heightened, but rather than leading you to idealize them, it creates a need within you to assume some form of control over them. This kind of association is usually tinged with insecurities, a hint of paranoia, causing you to behave in a way you usually would not. It might also seem strange, deep and foreign to your friends and acquaintances.
Venus represents love, Pluto represents power. The person whose Venus forms a powerful aspect to another person's Pluto will be "entralled, even obsessed, consumed with attraction" for that person, but that person will ultimately decide on the fate of the relationship. For example, Pluto in Scorpio will inspire a powerful attraction in a Venus in Scorpio individual.
Venus represents love, Uranus represents change and unpredictability. The person whose Venus- forms a powerful aspect to another's Uranus will probably see him or her as exciting and unpredictable. This could led to curiosity, romantic feelings, idealization, the urge to learn more, also disillusionment (if other aspects are unfavorable, insecurities (because of unpredictability). Uranus usually creates a loose association that cannot be tied down to conventional patterns, which must allow room for different kinds of development.
Mars represents physical attraction, Pluto represents Power. In some ways, this aspect goes both ways because Passion and Power are inextricably linked. Supposedly, the Mars person will be passionate for the Pluto person who retains the upper hand in the relationship; it is also possible for the Pluto person to be enthralled by the Passion in the Mars person, and for the Mars person to see the Pluto person as a source of power.
This is a powerful aspect in Male charts. Moon represents the Home and Hearth, and the Moon of a Male Chart will indicate the type of female he is able to envision being at home with or is comfortable with. For example, Aquarius Sun with Taurus Moon and Scorpio Ascendent (i.e. Taurus Descendent) will be doubly attracted to a female Taurus, despite the fact that he has 3 Fixed placements (Aquarius, Taurus, Scorpio) and is likely to clash with another Fixed sign.
Sun- North Node
North Node plays a relative small role in natal charts, but generally speaking, South-North Nodes represents the energies that you are moving away from and towards. If a person's Sun falls into your North Node, you are likely to see the person as possessing certain desirable qualities that you wish to imitate. If a person's Sun falls into your South Node, you are likely to empathise and identify with that person, but might not wish to enter into a close relationship with him or her.
7th and 8th House
7th House is governed by Libra, representing intimate union: romance, early stages of courtship, marriage. 8th House is governed by Scorpio, representing deep entanglements: shared resources after marriage, sex, death. If your 7th or 8th House is aspected in your natal chart, it could give you an idea of how you behave in relationships and your "ideal" relationship. For example, if you have Scorpio in the 7th House, it would indicate that you take relationships very seriously and your "ideal" relationship is always overshadowed with pain, parting, and you do nothing halfway when it comes to love. If you have Capricorn in the 8th House, this would indicate that you approach the idea of shared creation and resources (sex, birth, death, business) with a very cautious, uptight attiude.