Use line breaks to tell LaTeX where the new paragraphs begin.
I would not recommend using \\
: it will most likely not accomplish what you want and also send underfull box errors to you. If you want a list of some sort, there are three basic flavors: enumerate
, itemize
, and description
. I've illustrated enumerate
below.
Also, there's the enumitem
package which allows you to pass various parameters to your list environment controlling a lot of the spacing (vertical and horizontal). I illustrated a rather drastic version of this below (I don't recommend my choices of values).
\documentclass[a4paper,12pt]{article}
\usepackage{lipsum}
\usepackage{enumitem}
\linespread{1.3}
\pagestyle{empty}
\begin{document}
\begin{center}\LARGE
Topic
\end{center}
\lipsum[1]
\begin{center}\Large
Introduction
\end{center}
\lipsum[1-2]
\begin{enumerate}
\item first line
\item second line
\item third line
\end{enumerate}
\noindent%
Before an very scrunched up item list (probably not a good choice)
with a big indentation before each item:
\begin{itemize}[topsep=0ex,itemsep=0ex,parsep=0ex,leftmargin=4em]
\item apple
\item orange
\item peach
\end{itemize}
After list
Maybe a list is not what you desire; maybe you're trying to write
questions for an exam or quiz and want to leave spaces for answers.
You can force a prespecified vertical space by using
\verb=\vspace{...}= where \verb=...= is some length.
\noindent
\textbf{Question 1:} What is the meaning of life?
\vspace{1in}
\noindent
\textbf{Question 2:} Is this really a questions?
But there's not much space left here for an answer.
\end{document}
Note that the large line break in the image is due to a page break.

LaTeX
of making 'idiotic' and 'stupid' decisions reflects more on the user than it does on the software.