Your audience is more likely to accept your argument if you seem to be professional, fair and objective. You can do this by presenting the evidence both in favor and against your position, acknowledging and defending the weaknesses in the evidence that supports your view and counter-arguing against the contrary views or evidence with well-reasoned argumentation.
Avoid oversimplification, overstatement and emotional language, all of which can damage your credibility.
Avoid abbreviations. Do not use &, w/, #, or "etc." Spell these things out properly. If there are further items in your list, you should list them rather than using "etc."
Be especially careful to fairly represent the importance or impact of facts, findings and implications, whether they are your own or those of another author.
When characterizing the literature or critiquing a study, do not claim that it was the worst thing that ever happened or the best thing since sliced bread. Statements like this cast the world in black and white and it is best to avoid that kind of oversimplification.
Finally, avoid editorial expression of shock and awe. Your findings may have been unexpected but they should not be referred to as "shocking," "astonishing," "incredible," "unbelievable" or anything of the sort. Remember: You're trying to be as objective as possible.
While pointing out the limitations of your own argument or study may sound weak or wishy-washy, social scientists engage in a lot of this kind of qualification, and for good reason. No study is perfect and there is always the chance that there is another possible interpretation of the data or that the effect we are seeing is the result of some factor that we have failed to take into account. For this reason, when social scientists interpret their finds and come to conclusions, they are often careful to qualify their results by acknowledging competing explanations and confounding factors that should be considered. At the very least, we are likely to restrict our conclusion to the population that we have sampled For example, if I studied whether a library orientation program could reduce library anxiety in a group of undergrads, I should restrict my conclusions to undergrads, rather than claiming (or implying) that my results are applicable to library users in general.
This brings us to a dirty word in social science: proof. Never claim that your study (or someone else's) has proven something to be the case. Carl Popper has argued that absolute proof of a thing is not possible and the best we can hope for is to support our theories until they are demonstrated to be untrue or incomplete. For this reason, responsible social scientists say that theories or hypotheses are supported or not supported by the results, but not that they have been proven or that the results of the study provide "proof."
Note: While it is important to avoid overstatement, it is equally important to assume a stance and defend it by marshalling the evidence that supports it. In other words, you need to have a point of view on your topic and not be shy about asserting it; just make sure that it is a supportable position. That doesn't mean that it has to be unassailable or non-controversial: Your argument may boil down to demonstrating that your approach or conclusion is the best available in a sea of flawed options.
The idea that you should be assertive without overstating and provide support while admitting to limitations may seem confusing and contradictory. The key here is to be rigorously accurate about what is and isn't known and to honestly and accurately assess the strength of the evidence that supports current understanding and interpretation of the topic. It is reasonable to present evidence in support of your argument while simultaneously acknowledging the limitations of that evidence. By doing this, you will be seen as an objective reporter who can see both sides of the issue while choosing one of those sides with which to align yourself. This makes you seem more trustworthy to your audience and keeps you from painting yourself into a corner.
Also important to the idea of fairness is balance in your coverage of the available information. It is bad practice to only review or cite literature that agrees with you. You are obligated to point out dissenting opinions in the research and to answer these opinions with well-reasoned arguments.
APA is very clear that research writing should be concise: Say only what needs to be said and say it as efficiently as possible. This approach yields a manuscript that is more readable and increases the chance that it will be accepted for publication (or simply accepted by your audience).
It is, most regrettably, the longstanding and perpetual habit of a certain subset of grievously misguided student writers to engage in the profligate overuse of superflous words and this unfortunate practice has the unintended and ironic consequence of rendering the resulting prose far less accessible than it would otherwise be, to say nothing of the flagrant flouting of the goal of conciseness.
Translation: Some students use more words than they need, which makes their writing less clear and focused than it could be.
Perhaps this is a habit some people develop in order to fill up extra space and meet the page quota on assignments. Remember, however, that more words do not automatically make you sound "scholarly" and may even hamper effective communication with your audience.
The takeaway here is to use all the words you need, but use them wisely.
We are writing research articles, not crime novels, philosophical treatises or Victorian poetry.
People sometimes have ideas about "scholarly writing" that lead them to write in a way that is neither natural for them nor as clear as possible. The point of writing a research article is to clearly communicate your ideas without embellishment or digression. Anything that gets in the way of that goal should be avoided.
A. Words.
Sometimes students (and professionals) think that using lots of big, fancy words makes their work sound scholarly. It doesn't. That doesn't mean you shouldn't use "big" words if they are the most appropriate choice for expressing your intended meaning but it means that you should not use them for their own sake. Certainly, you should not use them if you are not absolutely sure of their meaning (see the entry on inapt words in the grammar section). The point of writing a research article is to clearly communicate your ideas, not to demonstrate your impressive vocabulary.
B. Syntax.
Complex thoughts sometimes require complex explanations. As with the notes on words above, though, complicated sentence construction for its own sake is not helpful. That said, we must strike a balance between the monotony of sentences with a simple 'subject verb object' construction and more complicated syntax.
1. Choppy writing. Short sentences are not bad. They can be good. They can provide variety. Having many is bad. There is no variety. You sound simple. That is not good.
If you find that you tend to write in very short sentences, try using conjunctions to join two or more of those sentences into a more sustained and complex thought.
2. Contorted syntax. If, when you are reading, you are finding, one after another, clauses which, for want of a better word, are "matrishkaed" together, nested in Russian-doll fashion, one inside the other, delaying, in most aggaravating fashion, your hoped-for and, it seems, constantly thwarted desire to finally, with a great sigh of relief, arrive at the point of the sentence, it can be, to say the least, aggravating, even if, grammatically speaking, there is nothing actually wrong with the sentence in question.
This sort of construction is not the only possible type of contorted syntax but the point is to avoid creating sentences that go on wild detours or start somewhere in the middle of the journey and work their way out. If you're writing a novel, go ahead: This sort of thing can can have its uses. In a research article, clarity rules.
As a last word on scholarliness, my advice is to strive for clarity and objectivity. If you tend to write with a few more "fancy" words and more complicated sentences, that's fine; just be sure that you are being as clear as possible. If, on the other hand, you tend to write in a simpler, more direct way, that's also fine. Do not go running the thesaurus to find obscure synonyms in an effort to sound learned. Although some students feel that the "just the facts, ma'am" approach of APA is dry and stifles their creative freedom, it is entirely possible to follow the rules and still have your own voice.