Why is the sky blue?

Getting right to the point :)

1. Light is divided into range. When it is refracted, it decomposes into seven colors (like a rainbow). This was first described in detail by Isaac Newton who passing white light through a prism.
2. The Earth's atmosphere does not lights itself. As the prism, it only refracts incident light. In particular, the sunlight.
3. The sunlight in the atmosphere interacts with air molecules.
4. Different colors in the spectrum have different frequencies. Blue has the highest frequence so we used to see the blue sky.
5. Sunsets and dawns can be red, yellow or orange. This is due to the deviation of sunlight. Blue light passes atmosphere and we see the lowest frequence ^^

How to play well in Dota 2?

Popular game but very difficult for new players. I'll try to describe some main points to win ^^ It can help novice and more or less experienced players :)

In the game:

1. Choose your best heroes and under the current situation.
2. Help with the pick of your team if you have some good ideas.
3. Buy or monitor that there are courier and wards for the whole game. Smokes, dusts and gem if nessesary.
4. Communicate with the team. Better in the voice chat. Give all the important information to your teammates and coordinate actions with them. Lead if you confident :)
5. Watch out for the game. Timing of creeps and Roshan, skill cooldowns. Enemy's items and the presence of buyback etc. Use this information.
6. A common good tactic looks like this: Stay good on your lines - gang others - win the 5x5-fight - destroy all external towers - kill Roshan - go into the enemy base.

Out of the game:

1. Watch the tournaments and professional players streams. Notice what and for what reason they are doing :)
2. Read the guides, watch tutorial videos, listen to the advices of your experienced friends who are also playing.
3. Follow meta of the current patch. Which heroes now "fashionable" and what strategies are relevant.
4. Watch replays of your games and notice your mistakes.
5. Find a good friends to play five team :)
6. Recently, OSU! bacame popular among pro players. It helps to warm up, improves concentration and reaction speed.
7. Devices and settings. Convenient mouse, a large mousepad, responsive keyboard and a large monitor. Play better on the lowest setting independently of your computer.

I think that is enough for now :) Anyway, Dota 2 is very complicated game so it is impossible to write a whole guide. But these advices can help you play better and win ^^