You must first ask yourself several questions: what do you want to observe, at what time and at what time of the year? First obvious thing to do astronomy, it takes a clear sky with very few clouds, without mist or fog. If the grass is wet, for example, at the end of the day and it is quite cold, there is the risk of fog during the night and you will not be able to easily see the stars.
With the Sun it’s easier. If the sky is clear, you can observe it at any time of the day. The ideal is to observe it during the noon hour because its image will be little disturbed by the turbulence, the light of the Sun crossing a layer atmospsheric thinner than the morning or the evening. It also shines much louder at noon and gives more contrasting images.
To observe the Moon, the planets, the stars or the galaxies it is necessary to wait until the night. In reality these stars also shine during the day but the Sun is so bright in the sky that you no longer see them.
In our latitudes (40-50 ° N) it is preferable to observe the sky in winter, when the weather is dry and very cold because the sky is often more limpid than in summer. Moreover it is night very early, around 17h and in the morning it can still be night at 8h. In winter you have the opportunity to observe the sky much longer, before going to bed or early in the morning as well as during the weekend or holidays.
Enjoy the winter because it is during this season that you will be able to observe the most beautiful constellations: Orion, Lyre, Cygne, Scorpion without mentioning the constellations that are always visible like the Big Dipper or Cassiopeia and clusters of Known stars such as the Pleiades M45, Praesepe M44, the globular cluster of Hercules M13, the Great nebula of Orion M42 and the Andromeda galaxy M31.
These are all objects to be observed that will give you a good reason to buy an atlas of the constellations. We shall return later to the constellations and all the stars that inhabit the universe.