Did you ask your teacher for some ideas too? I hope you did. If you are just starting, of COURSE your playing is uneven. I’m hoping that when your teacher tells you this (s)he gives you some ideas for correcting it as well.
On harp playings the notes of scales is very easy in any key, unlike the piano. However what makes scales hard on harp is playing them evenly, so focus on that. Start trying simply to keep the loudness and tone same though out. Later on practice playing scales in cressendo and decrescendo. When you start paying attention to what causes the loudness to change you automatically start learning how to keep it even as well.
And the Salzedo exercises are great for this kind of thing as well, but start with scales. Also runs or arpeggios. In fact if I recall correctly when I needed to focus on this my teacher had me playing arpeggios before scales.
We all have this problem at first so don’t feel bad about it. Just keep practicing and working on it and you will eventually develop full control over the dynamics of your playing.
Irene- I think you make an excellent point. The term “uneven” doesn’t mean anything in music unless it’s attached to something else. Rhythm-tempo-tone-volume? I think the first step towards improving the “even” sound is to find out what your teacher is describing. Then the teacher can select the elements that need to be practiced to increase more even _________. That’s what she’s being paid for!