In my post Who Cares About Majority Control Anyway? I make the point that having majority ownership of a company's common stock typically doesn't necessitate having control over the company's key decisions.  Since a vote of the common shareholders is just one of the three mechanisms by which key decisions are made in corporations a majority owner of common could lose control through the other two voting mechanisms.  To be clear, a shareholder can lose control of a corporation despite having a majority of the company's common stock or, conversely, stay in control of the company with only a minority stake.  It all boils down to their positioning across the three decision making mechanisms. 

This begs the question, "how can you maintain influence in key decisions made through all three mechanisms?"

There is no easy answer to this, as your ability to maintain influence is often a function of the negotiating leverage you have with potential partners (investors, employees or others).  Obviously, the less you need what your partner is offering (e.g., capital, expertise, etc.) and they more they want to be a part of your venture, the more likely you are to be able to obtain terms that leave you with control of your company.  In this extreme case you could give yourself special shares with more common votes than those allocated to your partner, disband the board of directors and eliminate a vote of the preferred shareholders.  In practice, however, few negotiations can be characterized by an extremely asymmetric balance of power, leaving both parties to compromise.  As a result, shareholder are often left to seek control of companies within the typical control structures.

This means seeking the best possible position in each of the three control structures.  There are, however, some tactics that entrepreneurs can employ to improve their influence in each control structure.

• Vote Of The Common: In theory, founders maximize their positioning in the vote of the common by ensuring that they can influence the greatest percentage of the common votes as possible.  In practice, this means selling the least amount of equity possible.  Often this can mean acquiring as few resources as possible (capital and talent) as late as possible in the life of the company - when the company's value has appreciated.
  
  It is important for founders to remember that they may be able to influence more shares that they own directly.  The votes of allies can provide founders with more leverage, often giving them the boost they need to win a contested decision. 


• Vote Of The Board Of Directors: Similarly, founders often seek to influence board decisions through allies.  By filling board seats with 'yes-men' or people with aligned incentives or similar ideology, founders can acquire the votes that they need to influence the direction of the company.


• Vote Of The Preferred Shareholders: Lastly, founders can seek to increase their role in a vote of the preferred shareholders by co-investing in the company to obtain preferred voting rights.  Additionally, entrepreneurs can mitigate the power of the preferred shareholders by negotiating for key decisions to be made by other mechanisms than a vote of the preferred shareholders.  Simply put, by having more decisions made by mechanisms where they have influence, founders can exert more control.

It is important to note that sophisticated investors are aware of these tactics and will see them coming.

Taking a step back...

Seeking a fair deal with regard to both the economics and control of the company is important and worthwhile.  If you have reasonable expectations and are working with a good partner, however, these conversations shouldn't be too painful as many of the terms and structures offered in these deals are increasingly boiler plate.  In other words the ending control structure of the company isn't something that is likely to vary too greatly from deal-to-deal.