The problem with this sentence is not so much the repetition of "ideas" as the entire content and construction. It sounds like a translation from a Chinese sentence. At present it is just a lot of words that do not mean anything. What are you trying to say? Could you post the entire paragraph so that we could correct it in context.

I suggest you consider the following framework and develop your essay from there: 1. Designing an experiment requires careful thought. 2. I have some preliminary ideas, but these require considerable refinement before they may become a rigorous basis for the experiment. 3. I am therefore gathering further intellectual input by reading additional authoritative literature on the subject. If you wish to improve your own ability in academic writing, you need to immerse yourself in good academic writing in English. You need to read much more academic writing in your subject published in the leading international journals and learn not only its writing style, but more importantly, its way of thinking. At present you are thinking in Chinese and your syntax and vocabulary are from a different planet, as it were.