Just knock the door 3 times is enough and no need speak out that how many days u staying there... When the time u knocking the door already telling them, a signal  that you are ready to entering the room...

Then, switch all the light and open wide the windows.. Most important is let the room get some sunshine.... After that, flush the toilet even u are not using...

I found this helpful:

Rule No. 1 – Knock the door before you enter the room
This is said to “inform” the spirits that you are about to enter the room. Its a polite gesture so the spirits might not feel offended if you just barge into their room

I did this, also each time I came back from outside I will knock again.

Rule No.2 -Flush the toilet as soon as you enter the room
This is say to flush away all bad things

  I didn't flush 1st, I pee 1st and then only flushed, is it ok?

Rule No.3 – Cover the mirrors in the bedroom
Remember to cover the mirrors. This is to ensure that they are not staring back at you from the other end

I didn't cover it, and I didn't look at the mirror many times too.

Rule No.4 – Make sure your shoes are both in opposite faces. Eg, one half of the shoe faces up, the other half faces down
This is to have the yin and yang effect. A natural balance in the room

Yea I did this. Last time my friend said if the shoes are arranged nicely, the spirits will wear it and next day the shoes will be somewhere else, is it true?

Rule No.5 - Don’t leave the bed unattended (Double bed rooms)
This only applies if you are not occupying the other bed. Make sure you put things on the bed. This is to ensure you are not inviting any invisible visitors to spend the night in your room. In fact, I have a friend that finds any of his stuff to put around at even the chairs.

Yea I knew about this, and I really put a lot of stuff next to me

Rule No. 6 – Leave the bathroom lights on at all times
Spirits like to hang around at damp and dark places and your bathroom would seem inviting if the rest of the room has lights on. By switching the lights on, spirits might probably find your room inhabitable

Not just bathroom light, the room lights are also turned on for the whole night I sleep. I don't want to risk it by turning it all off.

Rule No.7 – Always request for double bedroom
This only applies to those traveling alone. Its said that by ordering another bed, you would not face a situation where the spirit might just be sleeping next to you as you can’t even occupy the whole queen sized bed by yourself.

Yea mine is queen sized

Rule No.8 – Say “NO” to rooms near exits
They say that rooms that are next to exit (emergency) areas usually attract more spirits than other rooms. Why? Its because of the lonely and deserted stairway that attracts these spirits. And because they travel easily (through walls), they tend to linger at the next room just to disturb the unfortunate inhabitant.

Luckily my room is not next to it