I spend much of the fall each year helping executive teams conceive and produce their strategic plan for the next year.

And over the space of 30 years of doing so, I've discovered this: The reasons why otherwise well-written plans fail in execution the next year are unfailingly the same--irrespective of the size or nature of the business or the industry it's in.

Whether written by a small team of hot-shot over-performers, outsourced to a so-called consultant, or laboriously constructed through a series of committees, off-sites and re-writes, these same four nemeses continue to derail actual execution:

1. Your plan is a reaction to this year's challenges.

It's a natural enough thought process: This and that went wrong this year (the sales team underperformed, the warehouse got in the weeds, our IT system went down too often), so let's fix that. And voila, you have a strategic plan.

Except you haven't. You have a punch list--or a list of tactical measures, at best.

Strategy doesn't work like a game of ping pong--you don't make strategic progress by batting back what was thrown at you the previous year (that's a fine thing to do, but it's merely a hygiene factor for success).

2. The plan is focused on what you know.

Okay, so that line sounds like one of those smart-aleck business author come-ons, but the reality is very simple: We all tend to base the starting point for our strategic planning on what we know (accounting, engineering, sales, marketing...your mileage will vary). So far, so good. It's what happens next that makes the difference.

Many strategic plans stop right there--those universally turn out to be the weakest plans when faced with the reality of execution. Some plans go further, and deal with what the team knows they don't know. Maybe market demographics are shifting, or new technology is entering the industry, or new legislation is threatened, and while you and the team know about those changes, you also know you don't know what those changes will mean to your business. A strategic plan that addresses those issues (usually with the help of a subject matter expert) will be stronger, more robust, and more likely to succeed.

The most robust plan? One which addresses what you don't know you don't know. Think about it--where has your business most stumbled in recent years? I'd be prepared to bet it was as a result of something you never saw coming in the first place. This article will help you overcome that deficit in your plan.

3. Great ideas. No action plan.

When the production of a strategic plan is dominated by the influence of Visionary leaders, the result is often one which reads wonderfully--inspiring, sweeping, revolutionary, bold--but which lacks the granular detail necessary to ensure effective execution. (I'll show you how to overcome this weakness after the next section.)

4. Too many moving parts.

Conversely, when the strategic planning process is dominated by Processors (which often happens in larger organizations), the end result is often so detail-heavy, with so many moving parts, that it's un-implementable--the plan simply sinks into oblivion under its own weight.

The answer to both 3. and 4. is to ensure you have the third type of leader--the results-oriented, real-world Operators intimately involved in the planning process. They act as your best gatekeepers to reality, and will ensure the plan can actually be implemented in the real world.

Make sure your strategic plan for 2015 is successful. Join us at Inc.'s New York City headquarters for the ultimate year-end strategic workshop led by Les McKeown. Get details here.