A transit is one thing: a body currently moving through the sky forming an angle to a fixed point in your birth chart. That is the whole definition. Everything else - the tone, the warnings, the advice about what not to sign - is interpretation stacked on top.
Separating the two makes transits far more useful, and considerably less alarming.
Find the date, not the mood
Every transit has a moment when the angle is exact. Before it, the orb is closing and the aspect is applying. After, it opens and the aspect separates. The exact date is the anchor.
Without it you get "Mars is squaring your Moon this month", which is unfalsifiable and slightly ominous. With it you get "exact on the 9th, in orb from the 5th to the 13th", which you can compare against what actually happened on the 9th. One of those is astrology you can learn from.
Speed decides how much attention it deserves
The Moon transits everything in a chart every month, and each contact lasts a couple of hours. Treating those as significant events is a fast route to permanent anxiety.
Mercury, Venus and Mars move quickly enough that their transits are measured in days. Jupiter and Saturn take months. The outer planets can stay within orb of a single natal point for a year or more.
A rough rule that saves a lot of grief: the slower the body, the more weight the transit carries, and the less useful it is for explaining what happened on a Tuesday.
Why the same transit happens three times
Outer planets go retrograde. A planet applies to an aspect, goes exact, then stations and turns back, crosses the same degree a second time, stations again and comes forward for a third pass.
This is why a Saturn transit that "already happened" in March returns in August and again the following January. Nothing has gone wrong. The geometry repeats.
People who track only the first pass end up confused when the theme comes back. People who have the station dates can see the whole shape in advance and treat it as one long arc with three peaks - which is much closer to how such periods actually feel.
Natal chart first, transit second
A transit does not arrive in a vacuum. Jupiter crossing the Midheaven means something different depending on what is already at the Midheaven and what rules it. Generic transit descriptions cannot know that, which is why they read as vague - they are averaging over every chart at once.
The practical version: before reading what a transit "means", look at what it is hitting. Which natal planet, in which house, ruling what. The transit is a visitor; the natal placement is the resident.
Keep a record, then check it
This is the step almost nobody does, and it is the one that turns transits from belief into something you have evidence about.
Log something small each day - mood, energy, whether anything notable happened. Thirty seconds is enough. After a few weeks you have a record that was not written to fit a theory, because when you wrote it you were not thinking about the theory.
Then line it up against the transits that were actually running. Some will correlate with your own entries and some will not, and that result is about you rather than about astrology in general. It is also the only version of this exercise that is not circular.
What to do with a transit you have been warned about
Saturn returns, Pluto squares, the ones with reputations. Three things help.
First, get the actual dates, including the retrograde passes, so you know the shape rather than dreading a whole year.
Second, read what it is contacting in your own chart rather than the general description.
Third, notice that the frightening reputation attaches to the aspect in the abstract, and that a great many people have had the same transit without the outcome the description implies.
A transit is a description of where two things are relative to each other. It is not an instruction, and treating it as reflection rather than prediction is both more accurate and considerably easier to live with.