THE KEY CONCEPTS IN UNDERSTANDING AND ACHIEVING THE MOST IMPORTANTANT MILESTONE IN ALL OF PERSONAL FINANCE.

Before we cover the key concepts lets just quickly explain what is meant by this all important criteria.

This is especially important to define since there seems no formal agreed upon definition.

So with that...
The definition we will be using here is a single-dedicated account solely for the purpose of the setting aside of one hundred thousand dollars.

There is no other purpose for this account.
No dipping into it for the next shiny thing, and no BORROWING MONEY to start it. 
You CAN in fact begin with any discretionary money from other places.
For instance if you have seven thousand in your checking account and only need two thousand for monthly checking expenses feel free to jump start your account with that five thousand.
Perhaps you have a savings account that is getting little interest at your local bank that could be far more useful in this new account.
Theres more information in the below numbered concepts.

1. Your first hundred thousand dollars is by far the most important achievement of personal finance.

2. You want to get to the first hundred thousand as fast as humanly possible.
Whatever it takes to get there you have to do and fast (except borrow of course).
The difference of only a few years is life changing amounts of money.
Lets take a look at two examples.

Example 1:
James opens an S&P 500 account with one of the big three brokerages (HIGHLY RECOMMENDED) and starting with no money deposits one thousand dollars every month.
In just six years and with a ten percent return he has (almost) reached the one hundred thousand mark ($96,757.89 to be exact).
If he never puts another penny in and just receives a more modest eight percent rate of return the (almost) hundred grand will swell to a total of over four hundred and fifty thousand (450,000.00) in twenty years.
Again not one more penny was added.
 More impressively the amount grows to NEARLY A MILLION dollars in thirty years ($973,641) making James a round up millionaire.

Example 2:
Liam opens his S&P 500 account the same day as James and receives the same ten percent return, but takes a more scenic route.
He also starts with nothing but only puts five hundred dollars per month into the account. Liam will need TEN years instead of six to reach his goal.
Bear in mind what this really means to you, the actual James or Liam of this story.
As year twenty the difference is literally TENS OF THOUSANDS OF Dollars yearly.

Let that sink in.
TENS OF THOUSANDS.
Those four years are nearly the whole world to you.
Remember you probably have some accounts lying around so it's not likely your starting at zero.
And even if you are theres a thousand ways to make a thousand dollars (see article).
 Do it in six or less. preferable much less.
Lots of people already have. Now It’s your turn.
Make this happen.

3. The first one hundred thousand is by far the most difficult. We have to face a number of uncomfortable truths throughout this website, and this is one of them.
Setting up an account and getting to a hundred thousand can be challenging.
Not impossible by any stretch but challenging.
Getting to a hundred thousand FAST is even harder still.
If you don't fully commit yourself it will take more than the less preferable example of ten years, or worse you might never get there at all.
You can positively count on dozens of setbacks along the way.

There will be expedited layoffs, roof leaks, car problems, root canals, school supplies, etc.
Just remember this, other people on your income level or lower have done it and in less time than four years.

Last but not least remember this.
While there will be setbacks along the way make sure you don't give up if it does take longer than thought. If you can't reach this goal in four years than make it in five.
Even though you want to get there as fast as possible what's most important IS THAT YOU GET THERE.
In other words, get there fast.
Your middle aged version of yourself will thank you.

The most often said criticism of the hundred thousand goal people usually say is generally along the line of "the sort of sacrifice means I will have no life at all" or words to that effect.
You will likely hear it all the time like Scrooge did.
There are more reasons that's not true than one can count.

First, it's your budget and you determine how much of your money you use for your version of fun.

Second, you can undoubtedly make/save far more money than you give yourself credit for.
Everyone can.

Lastly, spending money just to spend money gets old fast for most people.
While some people do have a legitimate issue with emotional spending, most people who fall into this category of simply not being deliberate enough with their money.
Also take into account that most people who are deliberately trying to side-rail you are doing so because they understand that they don't have what it takes to improve their own financial situation.
In other words learn to ignore the haters.