How to get the "Better Off Dead" achievement in Plants vs. Zombies

The "Better Off Dead" achievement can be completed if you get a streak of 10 in "I, Zombie Endless". I understand that much.

This mode is really hard and I cannot get my streak near 10 games in a row, although I cannot put my finger on my main mistakes. I am happy if I can win 7 in a row. Are there any common tactics I can apply to improve my game or are there any common mistakes I should avoid? For example I have no idea if it is always best to send single zombies, or if I should combine more than one zombie in some situations.

While searching the Internet for guides I found someone claiming that the use of the "Lead Dancer" Zombie is often key - a Zombie type I usually don't like to use. Under which circumstances is it good concerning cost and value?

You really have to know the advantages of each zombie and how best to counter the plants. Generally what I did was,

• Aim for the flowers to generate more sun.
• Use as few zombies as possible
• Get the Magnetshroom out in the start to be able to use the metal wearing zombies
• Digger Zombie can take a whole row of plants out for just 175 sun, if there are no Spikeweed, Starfruit and Split Pea. 50 sun for the Imp when all else is dead.
• Imp dies from very little, just use him as a collector or as a sacrifice.
• Conehead Zombie is the standard sacrifice, as he can survive longer and possible eat plants as well
• Pole Vaulting Zombie can be used to save a little sun by jumping over a plant that might otherwise kill normal zombie. Note also that it can jump away from the first attack made by Chompers
• Buckethead Zombie can get very far, just be wary of instant killers and slowers combined with a lot of damage
• Football Zombie is the fast and heavy hitter. He is just expensive. He can however often be cheaper than buying 3 or 4 coneheads.
• Last we have Screen Door Zombie, Dancing Zombie, Ladder Zombie and Bungee Zombie which are only situational. I seldom use these and I found they require more planning than the other ones.

I hope this is helpful and good luck getting the achievement.