When someone is posting on your talk page you get an automatic notification. That notification is a small sign followed by a long yellow box at the top of your page (for most browsers and settings). In all other cases you have to alert the other editor in some way, either by "ping" or by mentioning them in a link. This will result in just the notification sign on top of that user's page. So even if you respond on your talk page you still have to alert the editor you are addressing. If you want to get hold of me you write <nowiki>{{ping|W.carter}}</nowiki> resulting in {{ping|W.carter}} or <nowiki>[[User:W.carter|W.carter]]</nowiki> resulting in [[User:W.carter|W.carter]] and sign with the four "squiggles" <nowiki>~~~~</nowiki> at the end and hit "Save". There are some more, but these are the basics. And when you ask something on someone's talk page, you also create a new section so your question don't get entangled in some other conversation. If you are having a conversation with another user on some page, it is also customary to add that page to your Watchlist in case someone in the discussion forgets to alert.
The policy is to leave an answer on the same page as the question, keep the conversation intact unless there is some reason for moving it elsewhere. Like complicated questions at the Teahouse can be continued on the appropriate talk page.
For customizing your signature you will find information at [[Wikipedia:Signatures#Customizing your signature]], there is also this page: [[Wikipedia:Signature tutorial]] on how it's done and where you can find examples of signatures. When you have entered the new signature at "Preferences → User profile", the four tildes will automatically create the signature when you type them and click on save.
For making your user page look nice, see: [[Wikipedia:User page design center]]. You can also "clone/borrow/steal" the code from someone else's user page. Just ensure that you change it enough that it does not look like you are trying to impersonate the other user. [[Wikipedia:User pages]] is a good guide as to what kind of things are appropriate in user space. And when you use the work someone else has created, in the edit summary please attribute the work to them by naming the user you copied the content from. If you want to add userboxes you can start here: [[Wikipedia:Userboxes]]. There are also many, many customized userboxes floating around on user pages in the Wikipedia, if you find one you fancy just copy the code from the page. If you are further interested in defining yourself and your style there is also the [[Wikipedia:WikiFauna]].
There are many kinds of citation templates. The most common ones are [[Template:Cite book]], [[Template:Cite web]], [[Template:Cite journal]] and [[Template:Cite news]]. Each of these contain a number of parameters. You can pick as many or as few of these parameters to describe your source as you like. At each of these aforementioned pages there are a number of examples of what set of parameters to use. For a book with several authors or edited by someone else you just pick the parameters you think are appropriate. Here's an example of a fiction book with many of these features:
<ref>{{cite book |last1=Wales |first1=Jimbo |last2=Smith |first2=Jane |date=2001 |chapter=42 (section: On mistakes) |editor1-last=Jones |editor1-first=Jack |editor2-last=User |editor2-first=Any |title=How to edit the Wikipedia |url=https://en.wikipedia.org/wiki/Wikipedia:Your_first_article |series=16 |volume=4 |publisher=Wikimedia Foundation |location=Earth |pages=42–88 |accessdate=7 September 2014}}</ref>[1]
Resulting in this ref:
References
^Wales, Jimbo; Smith, Jane (2001). "42 (section: On mistakes)". In Jones, Jack; User, Any (eds.). How to edit the Wikipedia. 16. Vol. 4. Earth: Wikimedia Foundation. pp. 42–88. Retrieved 7 September 2014. {{cite book}}: |editor2-last= has generic name (help)
As you can see, I have chosen the parameters needed from the very long list at [[Template:Cite book]]. When the template is copied to the article and inserted in a ref, it is called a citation. These are put after the text they cover, preferably after a comma or some other punctuation, but can be put where it is appropriate (this is an ongoing debate).
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