1- Those levels are strong support and resistance levels on short term , the market usually respects those levels strongly.
2- If the market rallies into resistance levels , a sell-off is expected.
3- If the market sells-off into support levels, a rally up is expected.
4-I highly recommend using divergences techniques, to find possible turning point during the week!
5- The recommended time frame , the 1 hour and below.
6- In trending market, to find additional levels , for example,If we wanna find R4 for EURUSD pair , we take the difference between R2 & R3 , then we add it to R3 , the result would be R4 ....and so on........