Is it good idea to use arXiv for improving my paper? I have some rejections to my paper due to wrong selection of journals and the small mistakes done by me. The mistakes are so small for me but crucial to paper and can be fixed very quickly (less than a minute) by me. I want to improve paper by myself by taking a long time because no rejection yet happened due to some serious flaw that I cannot manage.

Since I am a beginner, can I use arXiv to improve my paper through feedbacks or by taking time to improve paper instead of sending to journals and getting rejections for small mistakes? Are there any drawbacks to put my paper in arXiv? 

Points favor to me :

1) No time limit.

2) Feedbacks and suggestions may come.

3) Fewer chances for rejection if I publish it to a sensible journal after using arXiv.
arXiv is not a good choice for obtaining feedback or informal reviews of papers.

arXiv is typically used for publishing pre-prints. It allows authors to disseminate a paper as well as enabling the paper to be cited in advance of traditional publishing. As such, it also allows authors to establish some claim of precedence on their work. Such papers are often published on arXiv with a note such as "Submitted for publication in &lt; journal >" or "Accepted for publication in &lt; journal >" since the publishing cycle can range from months to years in some fields.

I would venture that most readers will be other people working in the field, to see what work is currently being done. They are likely to have neither the time nor inclination to review and provide feedback on unpublished papers. It may vary depending on the field but I would expect that papers without an accompanying "Submitted ..." or "Accepted ..." note would have fewer reads, let alone feedback or responses.