This post explains how to pull your chart and why knowing your Rising Sign is essential to reading your horoscope. If you're just looking for a quick link to pull your birth chart, you can do so here.
On this blog and on my Instagram account, I talk a lot about planets moving through different signs and how they will affect you personally. How do I know what’s happening with you personally, when I’ve never seen your birth chart?
Each birth chart is broken into 12 pieces, or Houses. Each of those houses covers specific domains of life (check out my Quick Guide to the House Meanings in Astrology). When the Sun, Moon, planets, or asteroids travel through (or transit) a specific House, they activate those domains of life. Knowing what House is being activated is essential to understanding how a transit will affect you.
There are many different approaches to astrology and the drawing of birth charts, but the approach I follow is called whole sign houses. Following this method means that each House is occupied wholly by 1 of the 12 signs.
The set up of your personal chart is determined by your Ascendant (AC). The Ascendant point (AC) is the exact degree of the zodiacal sign that was rising over the eastern horizon at the moment you were born (in the example chart below, the AC is at 3 degrees of Scorpio). Where the AC is determines you Ascendant Sign (also known as the Rising Sign). The Rising Sign also determines the sign of the 1st House (in the example, the 1st House is Scorpio; Scorpio was the sign rising over the eastern horizon at the moment this person was born).
Since the Rising Sign always determines the 1st House, if we know that sign, we can determine the sign of every other House. The signs follow a specific order, from Aries through Pisces, and each house contains one whole sign following that order. In this example, the 1st House is Scorpio, 2nd House is Sagittarius, 3rd House is Capricorn, and so on.
When I write horoscopes, I am always writing them for your Rising Sign, because if I know your Rising Sign, I know the sign of your 1st House and of all of your Houses, and therefore when a celestial body transits that sign (for example, when Venus is transiting Sagittarius), I know what part of your life is being affected (in this example chart, Venus in Sagittarius is transiting the person's 2nd House of personal money, assets, and resources).
So how do you determine your Rising Sign?
To determine your Rising Sign and which signs occupy each of your 12 Houses, you need to pull your birth chart.
You will need your birth date, birth place, and as accurate a birth time as you can get (ideally from your birth certificate, though not all certificates list the time). The Rising Sign changes every two hours, so getting as close as you can to the correct time is important.
I would highly recommend that you use Chani Nicholas's free chart generator here. You'll be able to quickly get your chart, drawn according to the whole sign houses system, plus you'll get majorly useful interpretations of the planet placements in your chart. I only list it second to the Cafe Astrology link above because Chani requires you to give your email address to access your chart, and that may not be your preference. Both chart engines will produce the same charts, though Cafe Astrology's chart interpretations are aligned with modern astrology whereas Chani's interpretations are based on Traditional or Hellenistic Astrology, which I recommend.