The word どう can be used as a more casual way to say how than by using いかが, which is more formal.
| How was the weather? | お天気 は いかが でした か。otenki wa ikaga deshita ka. |
| How's the weather? | 天気 は どう です か。tenki wa dou desu ka. |
| How was the date with him? | 彼 と の デート は どう でした か。kare to no deeto wa dou deshita ka. |
In last sentence above, note how we can use の after と, making 彼と behave like a noun that modifies deeto.
Unlike いかが, the word どう can alo be used in combination with the verb する to ask which action someone will take.
| What will you do? | どう します か。dou shimasu ka. |
