When astrologers place the transiting planets around a natal chart, the result is called a transit biwheel. Here are some pointers in creating and evaluating them.
1. Place a separate natal wheel on the page.
Why? Because transits can only activate themes already present in the natal chart.
By having the natal chart handy, one can:
See which natal planets are most stressed (i.e. only receiving squares and oppositions and/or conjunctions with challenging natal planets). Stressed planets will react more to challenging transits, and feel more relief from ameliorating ones.
See the easy places. Natal planets that are strong and only receiving trines and sextiles (and conjunctions with natal benefics) will get motivated by challenging transits to act, and become very relaxed (even too much so) from positive ones.
See the focal points. When a focal planet is transited, the likelihood of major changes in the life (and life events) increases.
You can read my article on focal planets and what makes a planet prominent in a chart here.
[Currently, only Solar Fire and Prometheus can create pages with both biwheel and a single wheel (for the natal chart) on them.]
2. Limit the orb of transiting points. In the biwheel itself, it is a huge mistake to use wide orbs. Since planets have their strongest effects within a one degree orb, if you use orbs wider than three degrees , you will focus on events that are a long way off, at least where outer planet transits are concerned, and not focus on the energies happening right now.
3. Applying and separating. I use one degree orbs, and encourage you to also realize that applying transits are much more impactful than separating ones, so if your software supports making separating aspect lines as dotted (and applying as solid), use this option.
4. Pay attention to Conjunctions. One weakness of most astrology programs is that they do not draw a line between transiting and natal planets that are conjunct. This makes it easy to overlook conjunctions in biwheels, which are very major events. Look for them.
5. Notice transiting planets at angles, and ingresses. When a transiting point crosses one of the four angles, it's a very major event (especially for transiting Jupiter through Pluto). It is also worth paying attention to when planets change houses, especially the faster ones.
E.g. in Barack Obama's biwheel (above) notice that Saturn is crossing the top of his chart (retrograding over the 10th house cusp).
6. Nodal conjunctions and oppositions. The conjunction or opposition of the transiting node is a mini-eclipse. It can either block or exaggerate the expression of the natal planet transited, and is definitely ungrounding.
Including Vedic approaches
1. Look at the Vedic houses ruled by the natal planet. Since, in my experience, house rulership should be reckoned using the Sidereal Zodiac (i.e. in Vedic charts, using Whole Sign Houses), one can gain insight about what areas of life will be most affected by a transit by focusing on the themes of the houses ruled by the natal planet receiving the transit.
E.g. a transit to the Fourth House lord will affect ones home, Mother, car, and sense of well-being.
2. Transits can activate yogas. If a yoga-forming natal planet receives a major transit, breakthroughs represented by the yoga(s) it participates in may occur.
3. Vedic special aspects. The forward sextile and backwards square of transiting Saturn, and the trines of Jupiter, are particularly potent transits.
A prime example of this can be seen in the death of Paul Newman's son from the transits to Paul's chart. There are no transits by Uranus, Neptune, or Pluto, but the exact forward sextile of transiting Saturn to natal Saturn is the prime indicator of the event.
4. Pay attention to dispositors. In the Sidereal Zodiac, if a transiting planet's dispositor is in a planetary war, debilitated, or combust, then the transiting planet's expression will be disturbed. E.g. transiting Saturn in Libra will have very different effects when Venus is in Virgo, near the Sun, in a war, or even Retrograde.