I reviewed a research paper and found it to be well-written with no technical or language issues. How should I go about writing the review report for the paper?
If I write something on the lines of "the work is well-written and well-presented" and keep the review report succinct, I am worried that the editor might think I did not review it critically.
Just being well-written and correct is not enough. Why should someone read the paper? What are the new things that we learn thanks to this work? Why is it exciting, interesting or useful? Why should we care about it so much that it should be published in a journal? How is it advancing science? What was the state of the art before this work, and how did this paper change the world?
In your review, you should explicitly recommend either acceptance or rejection. If you recommend acceptance, your review has to convince the editor that the paper is indeed worth accepting. (Similarly, if you recommend rejection, you will need to convince the editor that the paper should not be accepted.)
If this concerns you, write something like:
This paper uses X to investigate Y. It is well-written and the conclusions are backed by the experiments performed. I have no concerns and recommend acceptance as-is.
If I write something on the lines of "the work is well-written and well-presented" and keep the review report succinct, I am worried that the editor might think I did not review it critically.
There is no such thing as a perfect paper. Even when a paper is technically sound and written in perfect English, there usually is something like an explanation that could have done better, a confusing notation, a missed connection to existing work, or a misleading emphasis in the abstract. You probably know this from your own writing that no matter how often you revised it in response to constructive critique, a reviewer can point out some obvious (minor) improvement.
As a consequence, when I am reviewing a paper (that I had not seen before) and had nothing to remark for a few paragraph, this is very likely because I became unfocused. When I receive a paper from internal review without any comments, I am suspecting that the reviewer did not put much effort into it.
And if I were an editor, an otherwise all positive review (as you are about to give) would carry more weight for me if accompanied by a list of minor issues. This demonstrates that the reviewer actually thoroughly and critically read the paper. It also somewhat makes it less likely that the reviewer is just blindly recommending acceptance of a crony’s paper. One of my own papers was clearly subjected to one more review than usual for the respective journal after receiving a short exclusively positive review.
Now, it is of course impossible to know the editor’s stance on this, unless you intimately know them. Also, things may be a bit different, if you have a reputation as a thorough reviewer and the paper in question is written by your known arch-enemy. However, I consider it unlikely that a paper’s chances are diminished by a list of minor issues clearly labelled as such. This should of course be accompanied by the things mentioned in the other answers:
A short letter saying the paper is correct and well written is OK.
The editor may want your opinion about whether it's important or interesting enough to meet the standards for this particular journal. Check your instructions.
You should go with what @Jukka Suomela suggested: explain why the paper is interesting, why someone should read it, etc. But there is another thing -- in my field, reviews often start with a few paragraphs that quickly summarize the work being discussed (usually in a pretty neutral way). This allows the reviewer to recap what they understood about the work, gives authors and others a chance to see if they misunderstood something -- and yes it also makes the review more substantial.
So in addition to positive feedback about the work, you can consider also including your own quick neutral summary of what you understood from the work.
The answer of Jukka Suomela was very nice and comprehensive. However, I would like to add some remarks.
Remember that there was a reason that the editor has chosen you to be the reviewer of the paper. Because he/she found you an expert in this scientific field not in the language or the technique of writing. Therefore you should be very strict about reviewing the paper and give feedback on every aspects of the study, including the literature, the novelty of the work, the details of the experiment (or the method that they have used), the flow of the paper, the language, etc.
Even if you find the study sound in every manner, which is very rare, then it is strongly recommended to write a paragraph about the study at the beginning of your review. This clarifies everything and then everyone understands that you have reveiwed the paper in a correct manner.
Good luck
