"加以润色" can be translated into English as "polish up" or "refine", depending on the context.
"Polish up" implies making something smoother, more elegant, or better in quality, often through minor revisions or improvements. For example: "I need to polish up my essay before submitting it."（我需要把论文润色一下再交。）
"Refine" suggests making something more precise, perfect, or improved in its form or expression. For example: "The author refined his draft over several revisions."（作者经过几次修改润色了稿件。）
Both expressions convey the idea of improving the quality or presentation of something, but "polish up" is more colloquial and often used in contexts like writing or speaking, while "refine" can be used in a broader range of contexts, including art, design, or ideas.