So, we cannot interpret the planets in the signs because the Composite is not a 'real' chart (for example: there are no retrogrades).
This leaves us with the delineation of the planets in the houses and the Composite aspects.
When delineating Composite Charts, you should focus on the most important configurations that we list below:
The Composite Sun represents the life force of the couple, the unity of both people, so any aspect to the Sun is crucial.
Also note the house position of the composite Sun.
Look for planets in the 7th house (if there are no planets in the 7th house, take a look at the ruler of the 7th house and its aspects).
It's best to have the Composite Sun in the 7th, 2nd, 5th or 11th house.
The Sun in a mutable house may point to an unstable relationship.
In a lucky Composite Chart, there should be more harmonious aspects than disharmonious or challenging ones in total.
List the mutual or replicated aspects between the same pair of planets/points that you can find in both natal charts.
Example: when in both natal charts there is an aspect between Mercury and Uranus and you find both planets aspected in the composite chart again, its principle is emphasized and significant.
According to some research, the most important aspects in a Composite Chart (and the Davison Chart) are the conjunctions and oppositions (orb 3°).
The closer the aspect, the more it gains importance.
When delineating Composite Charts, this should be your main focus.
If there are no conjunctions and/or oppositions, the relationship is likely not to endure.
In Composites of lovers, you will almost always find VERY exact or close conjunctions or oppositions (orb 3°, the closer the better) to natal personal planets or points (Ascendant, Sun, Moon, Mercury, Venus or Mars) of one partner. Example: The Composite Moon conjunct the Ascendant of person A.
List the aspect configurations (Grand Cross, Grand Trine, YOD etc.) and significant planetary activity in a certain house (stellia), Quadrant or hemisphere.
Check if there are close contacts between each natal chart and the Composite horoscope.
Strong aspects denote a relationship that will have impact and might be life-changing.
No contacts indicate a meaningless relationship.
Especially check any aspects from a composite point (the Composite Ascendant, MC or planets) to the natal Sun/Moon midpoint of each partner.
Pay attention to the composite nodal axis (Moon's Node) and the planetary aspects from the individual natal charts.
The Sun-Venus conjunction in a Composite chart brings adoring love and is considered one of the best aspects to have.
This conjunction denotes pure forgiving and unconditional love without judgements.
However, it does not necessarily result in marriage nor does it indicate a life-long lasting bond.
It just brings adoring love with or without all its tragedies.
A New Moon in the Composite Chart (Sun conjunct the Moon) is highly telling and auspicious too.
A strong 5th house can be a blessing.
The more planets are found in mutable houses (especialaly in the houses 6 and/or 12), the less stable the relationship will be, especially when the Composite Sun (representing the Life Force and core of the relationship) and/or Moon is (are) part of it.
Too much planetary activity in the 6th and/or 12th houses are too critical and may result in arguments, disputes and sorrow.
Uranus around the composite Ascendant-Descendant axis may kill the relationship too.
The union may be short-lived.
Composite Saturn trine the Ascendant-Descendant axis on the other hand may promote a long-lasting union.
According to some research done by the German astrologer Mona Riegger, the composite Sun is most often found in a cardinal house (1, 4, 7 or 10) between married people, in the fixed houses (2, 5, 8 or 11) between friends or in the mutable houses (3, 6, 9 or 12) when it's about short-lived encounters and meetings.