Here is a list of elements used in English-language Wikipedia to make the article you are working on more complete.

Useful templates for English Wikipedia

Infoboxes

Some articles require infoboxes, which summarize the article's most important information. Infoboxes always appear on the right hand side of articles, and have to be placed before the rest of the article's text.

Two examples

Here is the example for human hemoglobin, a protein, on the right hand side is the final result, beneath is the wikicode.

{{Infobox heteropolypeptide
 | heteropolymer = hemoglobin
 | polymer_type = heterotetramer, (αβ)<sub>2</sub>
 | protein_type = [[metalloprotein]], [[globulin]]
 | function = [[oxygen]]-transport
 | cofactors = [[heme]] (4)
 | image = 1GZX Haemoglobin.png
 | image_source = Structure of human hemoglobin. <span style="color:red;">'''α'''</span> and <span style="color:blue;">'''β'''</span> subunits are in red and blue, and the iron-containing [[heme]] groups in green. From {{PDB|1GZX}} {{Proteopedia|Hemoglobin}}
 | SubunitCount = 3
 | subunit1 = Hb-α1
 | gene1 = [[HBA1]]
 | locus1 = [[Chromosome 16|Chr. 16]] [https://www.ncbi.nlm.nih.gov/Omim/getmap.cgi?chromosome=16p13.3 p13.3]
 | subunit2 = Hb-α2
 | gene2 = [[HBA2]]
 | locus2 = [[Chromosome 16|Chr. 16]] [https://www.ncbi.nlm.nih.gov/Omim/getmap.cgi?chromosome=16p13.3 p13.3]
 | subunit3 = Hb-β
 | gene3 = [[HBB]]
 | locus3 = [[Chromosome 11|Chr. 11]] [https://www.ncbi.nlm.nih.gov/Omim/getmap.cgi?chromosome=11p15.5 p15.5]
|Formula=C2952 H 4664 O 832 N812 S8 Fe 4|C2952 H 4664 O 832 N812 S8 Fe 4=}}

Here is the example for en:King-Wai Yau, a scientist: final result on the right, wikicode beneath this sentence.

Infobox for scientist King Wai Yau on English-language Wikipedia

{{Infobox scientist
| name = King-Wai Yau
| image = King-Way Yau 2008 ARVO.jpg
| alt = photo of King-Wai Yau
| caption = King-Wai Yau delivering 2008 Champalimaud Award lecture at ARVO meeting
| birth_date = {{Birth date and age|1948|10|27}} 
| birth_place = Guangzhou (Canton), China
| citizenship = USA
| nationality = 
| fields = [[Neuroscience]], [[Biophysics]]
| workplaces = [[Johns Hopkins University]], [[University of Texas Medical Branch]]
| alma_mater = [[Princeton University|Princeton]] A.B. in physics 1971, [[Harvard]] Ph.D in neurobiology 1975
| known_for = mechanisms of sensory transduction in vision and olfaction
| academic_advisors= John G. Nicholls, Denis A. Baylor, [[Alan Lloyd Hodgkin|Alan L. Hodgkin]]
| website = {{URL|neuroscience.jhu.edu/KingWaiYau.php}} 
}}

List of science-related infoboxes

en:Wikipedia:List_of_infoboxes#Mathematics_and_abstraction
en:Wikipedia:List_of_infoboxes#Science_and_nature (Includes Astronomy, Biology, Geology, Weather, and other topics)
en:Wikipedia:List_of_infoboxes#Technology_and_applied_science (Includes Computing, Photograpy, and other topics)
For other topics, here is the complete list of infoboxes on English Wikipedia

How and why to cite references

On Wikipedia, an assertion needs to be backed with a citation.

With the visual editor, the "easy way"

To introduce it in a Wikipedia article, you can rely on the visual editor for most cases (books, websites, articles). You can click "Cite", stay on the default "automatic" tab, and insert, depending on what you are citing, an ISBN, an URL, or a DOI.

For a DOI, if it doesn't happen spontaneously, here is a link to an external generator : https://reftag.appspot.com/doiweb.py

With wikicode, the "hard way"

In certain cases, you will need to know the wikicode (for citing a thesis, for example). Below is an example of wikicode concerning an article, and further below, the links to the pages explaining how to cite books, websites, and theses.

For a scientific article

To achieve the following note,^[1] use the following wikicode:

<ref>
{{cite journal
|last    = Peyron
|first   = Marie-Agnès
|author2 = Olivier Blanc 
|author3 = James P. Lund 
|author4 = Alain Woda 
|date    = 2004-03-09
|title   = Influence of Age on Adaptability of Human Mastication 
|journal = [[Journal of Neurophysiology]] 
|volume  = 92
|issue   = 2
|pages   = 773–779
|url     = http://jn.physiology.org/cgi/content/full/92/2/773
|doi     = 10.1152/jn.01122.2003
|pmid    = 15277595
}}
</ref>

To cite another article, reuse all the values to the left of the equal signs, and fill in as many fields as you can.