Find Chord Progression for a Melody

[saidmrn]

Hello guys.
I have been studying music theory so i can play a song by ear.

I can easily find the scale and the melody for the song.
i know which chords are in a specific scale.

But i don't know how to find the chords i need to match my melody.

sometimes the chord i use sounds good and sometimes not .

Do you have any tips to harmonize a song ?

[quantum]

Hi and welcome to Pianostreet.

As a general guide, take the melody note you want to harmonize and find a chord that contains that note.  Eg: C major, melody note G.  Chords C, Em and G all contain the note G. 

For a starting point, try primary chords - chords based on the I, IV, or V degree of the scale.