I did look into the Past Lives links provided by @BryWisteria, but then decided to see if I could find anything out through my birth chart. The birth chart does have some clues into past lives & who you were as a person.
South Node
Your South Node is direct opposite your North Node. Your south node and your north node are not planets. They’re actually the points where the moon’s orbit intersects the ecliptic on the day you were born. The south and north nodes make up the lunar nodes. The north node describes the person you should work on becoming. In contrast, the south node offers an unfolding story of your loving and challenging relationships, your talents, and your abilities developed in past lives. Déjà vu experiences are tied to your south node.
The south node will give you both positive and negative information. It shows the qualities you bring into this life (from a past life), but it can also give you a lot of clues into who you were in the past life.
The sign your south node is in will show how you were in a past life. Keep in mind that your south node generally indicates the negative qualities that you had in a past life. While you can certainly find the positive qualities in your south node, the negative qualities tend to be the ones that stand out. When looking at your south node, see if you can figure out what kind of person you were and what qualities you had.
The house where your south node sits will show where your past life took place.
Lastly, your south node’s aspects will give you some pointers about what other elements were involved in your past life. Trines and sextiles are usually positive, while squares and oppositions indicate difficulty. Conjunctions are the strongest aspect, but they aren’t necessarily good or bad. A conjunction means that your past life was deeply impacted by the planet to which it is conjunct.
Saturn
Saturn indicates a lesson we had in a past life that we did not learn completely. Therefore, we must continue to learn that same lesson in this life. Saturn will show the limitations of our past life. In this lifetime, you will see those same struggles pop up in some way. It might not be the same, but the lesson will feel the same. Squares to Saturn can also indicate what souls you may see from that same past life.
Jupiter
Jupiter is one of the past life astrology planets that indicate karmic gifts. Jupiter will show you what you have earned through good deeds in past lives. It can also be beneficial to look at Jupiter and figure out what you did well in a past life. This can give you more clues as to who you were and how you acted.
Planets in Retrograde
Any planet in retrograde usually means that some events in that past life were so negative that the energy of this planet is suppressed.