It's great that you're seeking solutions, ally1784. Here's some advice to tackle the problem:
- Make sure to read the text multiple times. This will help you immerse yourself in its world, and absorb the language and thought patterns of the author. If you already have a confident understanding of the text, try and read their other works; this will further isolate the author's distinctive characteristics.
- It sounds like you've got an intrinsic understanding of what the author 'sounds' like, which is a good sign. I would advise you to break this down further: perhaps select some passages and annotate key features of the author's style. Which of the senses do they appeal to in descriptions? How much do they employ figurative language? What aspects are most emphasised about the text's environment? This is doubly helpful if you choose some less obvious sections of the text; it will help you identify subtle decisions and characteristics.
- Writing style is always shaped to fit an author's intention. It may be that your intention is not aligned with the textual values, and consequently the 'feel' of the writing does not carry over. If this is the case, you may want to reconsider your chosen topic; finding other areas or ideas you connect more strongly with.
Alternatively, you can always use your Statement of Intention! For example:
"I purposely deviated from the author's own style, using [evidence from your own piece] rather than his/her use of [evidence from the text]. I hence repurposed the novel for an [alternative audience], considering..."
Or: "By avoiding the author's use of [evidence], I challenge their views on [such and such], contending instead that..."
Hopefully at least some of this advice is helpful. However, it would be easier if we knew what text and author you were studying. If you'd reply with the answer, me and others on this forum can give you further and more specific help.