I do English editing almost daily, because I am a freelance English editor. I don't mind if some authors don't know how to write well in English, which is why there are so many editing companies these days, to help non-native speakers to write better. (Note: Not every native speaker can write well in his own mother tongue.) However, I do mind when authors put down things randomly.

Here are some examples:

1) Fig. 1: This is a common expression in papers. I have seen "Fig 1," "Fig. 1.," "Fig.1 (no space)," etc. In particular, more than one form was used in the same manuscript. If you are not sure which form is correct, check out the journal guideline for authors. If the journal does not care, you pick a common one and use it consistently.

2) Wang et al. (1999): This is simple enough for citing a multi-author paper. Well, somehow, some authors would dance with Wang, et al. (1999); Wang et al (1999); Wang et al., (1999); just to name a few. Sure, some journals may use [1999] instead of (1999). No matter what, using a consistent form should be simple.

3) Date: This is a bit "tricky." There are two ways: "Septembr 12, 2016," or "12 September 2016." I prefer the latter because it does not need comma. Again, if you are not sure which form to use, check out the journal guideline for authors. If the journal does not care, you pick one and use it consistently.

What other examples are there? I may add more once I have recalled them.

4) Decimal point: Use the same number of digits after the DOT, such as 1.234 and 5.678 (just for fun).

5) Indexes and indices: Yes, they are both corrent but can you please stick to one of them in one paper?