Naming of source files:
The name of a LATEX source file should be one word (no spaces, no special characters), and end with .tex.
(for example, myfile.tex)
Spacing in text and math:
Many spaces equal one space in text, whereas your spacing is ignored in math, unless the space terminates a command.
Use the align environment.
Separate the lines with \.
In each line, indicate the alignment point with &, one & per line.If the alignment point is adjacent to an =, +, and so on, place it before to ensure proper spacing.
Place a \notag command in each line that you do not wish numbered. If no line should be numbered, use the align* environment.
Place a \label command in each numbered line you may want to reference with \ref, \eqref, or \pageref.
When you work with a word processor, you see your document on the computer monitor more or less as it looks when printed, with its various fonts, font sizes, font shapes (e.g., roman, italic) and weights (e.g., normal, boldface), interline spacing, indentation, and so on.
Working with a markup language is different. You type the source file of your article in a text editor (such as, overleaf, texmaker, texworks, etc.) , in which all characters appear in the same font. To indicate changes in the typeset text, you must add text markup commands to the source file.
In a perfect world, all your documents would compile without problems and give you high-quality output. However, sooner or later, you will encouter problems of some kind. Here a few tips for dealing with errors:
Finding the source line of an error
MikTex will log all problems with the document in the Log tab, including the line at which the problem exists
"Undefined Control Sequence" is created by either making a typo in an actual command, or by having a missing library that contains the definition of the tag.
"Missing $ inserted" is triggered by attempting to use tags that are meant to be called within MathMode. To enable MathMode, wrap the text with $ symbols (ex, $ 5\pi = x $ )
"Emergency Stop" will not have a line number associated with the error because it is an error produced when the compiler has reached the end of the script, but was still waiting on certain commands to appear. A common way to create this error is to use a \begin tag without closing it with an \end tag.