Personally I don't like this kind of repetition, although it is used by some. I think it's preferable to repeat the example with a new number. But independent of this opinion, the effect is easily achieved with both the gb4e package and the linguex package.
gb4e
It provides an \exr{<label>} command, which formats the example based on reference to a label.
\documentclass{article}
\usepackage{gb4e}
\newcommand\extwo{Example 2}
\begin{document}
\begin{exe}
\ex Example 1
\ex \extwo \label{ex2}
\end{exe}
Text
\begin{exe}
\ex Example 3
\end{exe}
Text
\begin{exe}
\exr{ex2} \extwo% Example 2 repeated with its original number, i.e. "1."
\end{exe}
Text
\begin{exe}
\item Example 4% Is listed as "3." when I want it be listed as "4."
\end{exe}
\end{document}
linguex
It allows its \ex. command to have an following optional argument to set the label. This argument can contain a \ref{} command.
\documentclass{article}
\usepackage{linguex}
\newcommand\extwo{Example 2}
\begin{document}
\ex. Example 1
\ex. \extwo \label{ex2}
Text.
\ex. Example 3
Text.
\ex.[\ref{ex2}] \extwo
Text
\ex. Example 4
\end{document}
Instead of setting itemindent, you can change the values for leftmargin and labelindent:
\documentclass[letterpaper]{article}
\usepackage{fullpage}
\usepackage{amsmath,amssymb,amsthm,enumitem}
\begin{document}
To convert from general form to standard form, we will follow these steps:
\begin{enumerate}[leftmargin=*,labelindent=16pt,label=\bfseries Step \arabic*.]
\item Ensure the coefficient of the terms in $x^2$ and $y^2$ are 1 respectively.
\item Group the terms containing $x$ and $y$ respectively. Move the constant to the RHS.
\item Take half of the coefficient of the linear terms in both $x$ and $y$, square it and add it to both sides.
\item Rewrite the result in factored form.
\end{enumerate}
\end{document}
In fact, if some of your lists will have 10 or more items, the following settings would be preferable:
\documentclass[letterpaper]{article}
\usepackage{fullpage}
\usepackage{amsmath,amssymb,amsthm,enumitem}
\begin{document}
To convert from general form to standard form, we will follow these steps:
\begin{enumerate}[labelwidth=1.5cm,labelindent=10pt,leftmargin=2.2cm,label=\bfseries Step \arabic*.,align=left]
\setcounter{enumi}{8}% just for the example
\item Ensure the coefficient of the terms in $x^2$ and $y^2$ are 1 respectively.
\item Group the terms containing $x$ and $y$ respectively. Move the constant to the RHS.
\item Take half of the coefficient of the linear terms in both $x$ and $y$, square it and add it to both sides.
\item Rewrite the result in factored form.
\end{enumerate}
\end{document}
With the help of the layouts package and the following simple code
\documentclass{article}
\usepackage{layouts}
\begin{document}
\begin{figure}
\listdiagram
\caption{List parameters}
\end{figure}
\end{document}
you get a diagram showing the various lengths associated to a list:
the enumitem package adds another parameter \labelindent for the blank space from the margin of the enclosing list/text to the left edge of the label box. Here's the dependencies between the relevant horizontal parameters:
\leftmargin + \itemindent = \labelindent + \labelwidth + \labelsep
Only modifying itemindent changes the indention for the first line of the first paragraph of each \item, and this produces the undesired result in your example code; modifying leftmargin changes the indention for all the lines. Compare the results in this simple example:
\documentclass{article}
\usepackage[showframe]{geometry}
\usepackage{enumitem,lipsum}
\begin{document}
\begin{enumerate}[itemindent=3cm]
\item text
\item \lipsum[2]
\end{enumerate}
\begin{enumerate}[leftmargin=3cm]
\item text
\item \lipsum[2]
\end{enumerate}
\end{document}
Best Answer
Here is an adaptation of Good way to make \textcircled numbers? for your needs:
To increase the circle size, play with the
inner sepparameter (the border between the number and the circle). To change the color, play with thefillparameter.If you wish to change the text color, you can use the
xcolorpackage: