Without much more information about your tank (size, lighting, temp, stocking and water stats) it's very hard to advise.
However, you have what looks like Black Beard Algae on your plant leaves which is often caused by to much light. Treating it with reduced lighting and directed application of Glut or Excel can be effective.
I would scrape off the glass algae and syphon it out as a starter. Try improving water quality, reducing nitrates and go from there.
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