I believe proofreading is a very beneficial habit in writing papers, reports, chapters, ..etc. I trust some people who do that for me. Is there any website doing that?let us know what are you doing?
Once I complete a paper, I would let it sit for a few weeks or sometimes months and then proof read, revise, and edit. Sometimes, I also request colleagues and friends within the same field and outside the field. It helps me in identifying issues that I wouldn't have noted myself. Especially, people outside my own field can provide a good objective assessment of readability and comprehension.
Having colleagues proofread is very useful, as is proofreading myself after taking a bit of a breather from a particular piece of writing. I wouldn't recommend using online services for this; it's difficult to know whether the person doing the proofreading is qualified or appropriately engaged. Best to rely on people you know, and yourself, to ensure quality proofreading!
Like Ahtisham - I find that a good strategy is to complete an article/report etc as best one can and then put it to one side for a little while. It is useful to come back to a manuscript with 'fresh eyes' and one has had time to 'divorce' themselves from the initial writing rush. In my early days of publishing i.e. 15-20 years ago, I used to write very quickly and not proof-read. I would be surprised if reviewers were over-critical or I was rejected. I used to write mainly solo in my early career as well. I still enjoyed regular success - but it's a more competitive publishing environment nowadays and reviewers, more often, are more knowledgeable. Now - I mostly publish with other authors who proof-read and there is usually the strategy of passing it around in turn. This way - by the time it gets back to me again - I'm looking at it with fresh eyes again and I can objectively review additions made.
I agree with Ariel in terms of not using proof-reading/editing services for articles etc - but I do encourage it for thesis students as, for me, beyond initial chapter draft feedback - supervisors are not editors.
I agree to Dean Whitehead, once you are done with your article or paper, you take a break (depends on you) of hours or day or two. Then you come back and give it a second reading and if possible let someone narrate it to you while you just listen to what is written. Make appropriate changes and then you are good to go. I believe only the author can understand the full meaning of what s/he wants to say and mean. Thank You !