Just how do you "predict?"
The chart we choose to use determines "how effective" and "what we can see".
** TRANSITS to the natal chart: Outer planets may "play" with a natal planet for several months or even a year or two. Middle planets may "contact" a natal planet over a period of several days to a few weeks. Inner planets may hit upon a natal planet for just a day or two or three, while the Moon may transit a planet (using a tight orb) for only a few hours. Predicting "when" can be very tricky! Predicting "what" can also be tricky.
Planetary symbols tend to express themselves in as many ways as possible. The nature of a planet, and its links to other planets, in a natal chart will almost always affect the influence of a transiting planet.
** SECONDARY PROGRESSIONS are merely refinements of the natal chart. They show increasing and/or decreasing influences of aspectual contacts between planets of the natal chart. Often, only the Sun and Moon will move enough over a life time to mark significant shifts in how the natal chart might "develop" its potential. Predicting with this chart type shows developments and trends, seldom events.
** SOLAR ARC PROGRESSIONS move every planet by the amount of the Sun's movement from one day to the next -- equalling a year's development. Since the Sun is being focused upon, one's health, vitality, will and conscious choices are the focus of this chart. Within that context, these charts can be fairly precise in pointing to "when" an event can happen, and the recombined contacts between progressed and natal planets point to new experiences for one to live through and grow through.
** SOLAR RETURNS provide a "re-focus" theme for the coming year. First, they often place the natal planets in a different house context. Second, the transiting planets on the date of the solar return display their importance by their nearness or distance from the chart angles. Angular planets are very strong in their influence -- natal or solar return planets. This type of chart points to what you can expect during the coming year.
**** "TROPICAL" Solar Returns portray cultural and social influences that mark ones development and experiences during the year.
**** "SIDEREAL" Solar Returns portray events in terms of energy, anger, fears, and human reactions. The difference in what these charts portray is due to the "timing" of the charts. Tropical charts are linked to the Sun marking it's "sign". Sidereal charts don't use signs and are "angular" and aspectual in nature, thus emphasizing event experiences.
As we use these charts, in the order mentioned, we move from a broad "life" view to a more focused "month or period" view. For predictive purposes we need to move to a "daily" view. There are specialized charts for doing this, but it may not make much sense to go into these here and now. But, to do predictive work, you do need to be able to move from the general view to the highly specific view of life. Dave