You're probably familiar with the story for a jar that represents the time available in your life. You fill the jar with rocks, pebbles, and sand representing the big, medium, and small stuff you do every day. If you start with pebbles and sand, you'll run out of space for the big rocks--the things that matter most. But, by starting with the rocks, you'll still have room for the pebbles and sand; they'll just take up far less of your precious time.

A handy way to think about rocks is that they're large projects that have multiple steps and take a long time to complete. Pebbles are medium-sized, single-step projects. Sand to-dos take no more than five minutes to complete.

The problem is most people put rock, pebble, and sand tasks on one long list and become overwhelmed. Instead of slogging through the stack, we shut down or procrastinate. Or, we don't schedule enough time for the big rocks and give too much time to the small stuff preventing us from meeting important goals.

Here are four steps to segment your to-do list to help you prioritize the most important items, stay focused, and get more done.

1. Distinguish between rocks and pebbles

Everyone's definition of rocks and pebbles will be different. Invest a little time in creating clear distinctions, and you'll better prioritize the rocks. Experiment using these simple guidelines:

Rocks feels bigger than pebbles. Rocks are often a collection of prerequisites or multi-steps processes. An interview is a rock, for example, because you need to prepare for the questions and have the appropriate attire before you start. Rocks usually take more than 30 minutes to complete, while a pebble can be knocked out in a half hour.

Rocks feels heavier than pebbles. Rocks can have emotional weight. They create a sense of resistance or anxiety to completing or starting a task, even when we're not clear why. Pebbles, on the other hand, are effortless to tick off. You'll know you've discovered a rock masquerading as a pebble when it's a single step, but you don't want to do it. For example, you notice you're avoiding scheduling a one-on-one with your manager--a one-line email that will take 30 seconds to write and send. After some thought, you realize you're afraid that she's not happy with your performance. The task, then, isn't as simple as scheduling a meeting, but includes dealing with your emotions and prepping for the discussion. You might need to attend to additional details before scheduling, such as gathering data, calling a friend for support, going for a walk, and clearing your calendar afterwards to process the feedback.

2. Create three separate lists

To use your time well, create a list for each category. I even have a subsection under each for phone calls because I can make them when in transit or waiting for something. You can separate out work and personal items as well. Here's a snapshot of my list from last week:

Rocks

Pebbles

Sand

Write rocks vs. pebbles article

Revise handouts for icebreaker

Pay monthly business tax

Submit proposal for executive retreat

Consolidate points for empathy expert interview

Send M's invoice

Write keynote on personal courage

Pack for Irvine trip

Create new executive women's program brochure

Revise teaching points for Courageously You! workshop

Phone

Phone

Phone

Call friend X and ask him if he's angry with me

Call Dr. Koch to understand lab results

Activate new credit card

Home

Home

Home

Decide holiday travel

Make book club dessert

Send fall party invite

Have family conversation about device use

Create alterations pile

3. Break up the rocks

When you're overwhelmed by the number of rocks on your list, assign them an order and break them down into smaller steps. Perhaps you'll spend an hour on part of Rock One before moving on to tackle part of Rock Two and so on.

Don't spend a lot of time planning pebbles, however; it will usually take you less time to do them than to plan them.

4. For each rock, take the first small step

I don't like writing client proposals, so the evening before, I save the template under my client's name and leave the document open on my desktop. That first, tiny step lowers the barrier to starting the next morning.

Now that you can clearly segment the tasks on your list, when you find a rock overwhelming, instead of spending two hours procrastinating on a video game, you can tackle a few pebbles or some sand. Walking from one building to another on a work campus? Make that short phone call on your sand list. On hold with your doctor's office? Complete that LinkedIn recommendation for your colleague.

I often joke that it's great when I have a big, scary rock on my list because I get a lot of smaller rocks, pebbles, and sand done.