Reading the light before sunrise
Most people arrive for sunrise at sunrise. By then, the best colour has often come and gone.
On a clear morning with some high cloud, the underside of the clouds lights up while the sun is still below the horizon. The sky turns pink, then orange, then fades as the sun climbs. That window often lasts ten or twelve minutes, and it starts around twenty minutes before the official sunrise time.
Check the clouds, not just the sky
A completely clear sky gives soft gradients and little drama. A completely overcast sky gives nothing at all. What you want is broken cloud above 6,000 metres with a clear gap on the eastern horizon. That gap lets the low sun reach the clouds from underneath.
I check two things the evening before: the high cloud forecast and the low cloud forecast for the direction of the sunrise. If the low cloud to the east is above 70 percent, I usually sleep in.
Be set up early
I aim to have my tripod set and a composition chosen forty minutes before sunrise. Then the colour arrives and I only need to watch the exposure. Scrambling for a composition while the sky peaks is the most common mistake I see at workshops.
Expose for the sky
The foreground is still dark in this light. Expose so the brightest clouds keep detail, then take a second frame for the foreground. Blend them later, or use a soft graduated filter if you prefer to get it in one frame.