Solar arc direction is a very old, very simple and incredibly powerful predictive technique. It is just as important as transits, even though some of the big names in astrology don't use them. I have seen top notch astrologer miss predictive events completely because they don't use solar arcs.
I first learned about solar arcs when I studied with Noel Tyl about 15 years ago. In the lesson where he explained what they were and how they worked he warned us that we would be lying awake at night, calculating solar arc aspects in our head - and he was right! I was blown away by how they coincided with ... everything major in my life! If you are astrologically minded, this is fun! You don't need a computer program or even an ephemeris - you just need basic math. Try it out when you go to bed tonight - or before.
If you are not familiar with solar arcs, don't worry - they are so easy to use. You can approximate your solar arc aspects by using 1 degree per 1 year of a person's life, and then you move everything in the chart by that number. If you are 45 years old, you will move all your planets approximately 45 degrees. Try to think of your chart and move planets forward from early childhood onward.
If your Sun is at 1 degree of Leo and your Pluto is at 10 degrees of Leo, by the time you are around 9 years old, solar arc Sun will have moved 9 degrees to an exact conjunction with your Pluto - and you know something very important happened to you at that time. Even if there are no other major aspects around, something very deep impacted you at that time.
You will find that for everything major that ever happened to you - there was a solar arc aspect involved. If you start to think about your chart, you can start with those planets that are close to each, in or out of aspect. If in the example above Pluto were at 4 degrees of Leo, solar arc Pluto would conjunct your Sun at age 3! What happened? That could have been a major traumatic event for you - or perhaps something happened with your dad?
Just start out by thinking in terms of conjunctions and oppositions - they are easy to do in your head. If your Moon is at 14 degrees Cancer it will oppose your Saturn at 20 degrees Capricorn when you are 6 years old. Think about the emotional impact Saturn could have on your soft, sensitive Cancer Moon! Perhaps a conflict between your parents broke out or became clear. Maybe your parents divorced and it shut you down emotionally and in typical Cancer-style, you clammed up and closed off.
In addition to aspects, it is also important to note when planets and angles change signs by solar arc direction. Since every planet will be in any given sign for up to 30 years, most people will experience 2 or 3 different sign positions for every planet. Say, your Mercury was in Scorpio when you were born - a very deep, penetrating mind, maybe with a measure of obsessive compulsion and paranoia - maybe you grew up in a home where there were a lot of undercurrents. Maybe you grew up scared!
Let's say your Mercury is in 5 degrees of Scorpio in your natal chart. It will move into Sagittarius by solar arc direction when you are about 25 degrees and your mind will become involved with foreign cultures, higher education, publishing, travel, philosophy etc. You could start out on a quest to gain wisdom and understanding regarding Plutonian traumas that affected your mind, your thinking patterns. You may spend the next roughly 30 years on this quest, trying many things, greatly expanding your mind - and then, solar arc Mercury moves into Capricorn!
Relief, you say? Capricorn? Well, relief if you decide to use high Capricorn energy - learning to discipline and structure your mind and your thinking. Imagine engaging in a serious, long-term study of mind control - anything from Silva Mind Control, to Buddhist meditation or Andy Shaw's Saltori System for Structured Thinking. Learning to control your Mercury would surely be a relief after the mental roller coaster you may have been on your entire life.
Another example using the same archetypes would be if you had the Sun in 5 degrees of Capricorn. Then, at age 25, your Sun would move into Sagittarius and your world would greatly expand somehow. Maybe you decide to go back to college, maybe you move to another country - but the world will somehow open up for you. If your early years were restricted and you had to grow up too soon, this could be a time when you start to let down your hair and just have some fun. You might find a new sense of optimism - and maybe you would start to see your life as a quest as I mentioned earlier. The Sagittarius archetype is strongly linked with the Quest.
So, have fun tonight, and fall asleep to the hum of your solar arc aspects.