Yes.
Exactly that.
The notes of the triad are always going to sound great. At home. They totally belong. And because of that can sound predictable. Consider arriving at a chord tone from the scale note one above or one below.
If you find your melody is based around the root note of the C chord while it is being played, arrive at that note from B (below) or D (above).
If you find your melody is based around the major 3rd note of the C chord while it is being played, arrive at that note from D (below) or F (above).
If you find your melody is based around the perfect 5th note of the C chord while it is being played, arrive at that note from F (below) or A (above).
And in the key of C it is very obvious to the eye as it is all laid out in liner manner on the white keys.
And so on for other chords.
Also consider introducing a mixture of intervals within the contour of your melodies.
Steps - where the melody ascends or descends in moves of one scale degree. The immediately adjacent note.
Jumps - where the melody ascends or descends by thirds, jumping over the immediately adjacent note.
Leaps - bigger then jumps.