We use Present Continuous for 
1. things which are happening now or around now
am reading an interesting book now.
2. temporary situations
He is from Riga. He is studying in London at the moment.
3. changing situations
Her English is getting better. 
  • (right) now
  • at the moment
  • at present
  • these days
  • today/ tonight
  • this morning/ afternoon/ week/ month/…
  • Look!
  • Listen!
4. fixed arrangements in the near future
We are flying to Milan tomorrow.  
  • tomorrow
  • the day after tomorrow
  • tonight
  • next week (weekend/ month)
  • in a week (a month)
  • at 7 o'clock tomorrow
NOTE! Present Continuous is used with these key words only if we speak about fixed arrangements in the near future!
5. repeated actions expressing annoyance (usually with "always")
You are always losing your keys!
  • always
We use "Look!" and "Listen!" at the beginning of a sentence.
Listen! Somebody is coming.
We use "always" between "am/ is/ are" and "Ving".
He is always interrupting me!
We usually use other key words at the end of the sentence.
We can also use these key words at the beginning of a sentence if we want to emphasize them.
I am writing my blog now.
Now I am writing my blog.
Ving - Verb ending in "-ing" (Present Participle). E.g. writing, going, listening, etc. Revise how to add "ing" to a verb here.