Zero death challenge
A zero-death run is where one tries to accomplish completion of one of the Pikmin games without losing any Pikmin whatsoever. This can be very difficult, even for skilled players. However, there are a number of ways whereby this can be made easier, listed below.
Reset
Even if only one of your Pikmin dies, don't blow a hole in your wall, just press the "RESET" button on your console, or press the "POWER" button so it goes on and off. This is especially useful in caves, where your progress is saved between sublevels, meaning you will lose little progress. In Pikmin 3 you can just pause the game and select "restart area"
Take your time
Especially in the first game, where enemies can be a lot harder to beat due to generally higher enemy HP, the absence of Purple Pikmin, greater lag, and several glitches (like the crushing glitch), you need to take your time so as to avoid even the slightest of accidents; carefully avoid the enemies' attacks, and if you fail, you can always reset the game. Patience is vital when fighting difficult enemies like the Beady Long Legs and Emperor Bulblax, or the likes of the Titan Dweevil in Pikmin 2.
Use force
Some enemies are hard to beat without a large onslaught, so take the strongest forces of Pikmin you can muster, and use them correctly. In Pikmin 2, you should always try and defeat enemies with Purple Pikmin whenever possible, because it can be done with relative ease and takes less time. In the first game, there are also a number of alternative, safer ways to defeat enemies, such as using bomb-rocks.
Be sneaky
While the enemies that lurk on the main paths should always be dispatched, many enemies near parts and treasures that are on the road less traveled don't always have to be killed. Most enemies will follow a captain with or without Pikmin, so use a captain to distract a group of enemies while a small group of Pikmin slip by with a part or treasure. In caves, one should find the most direct route to the treasures and only kill the enemies on that route.
Don't overburden yourself
Although it may make the next few days a little easier, killing all the enemies in the level or trying to kill multiple bosses in one day will likely result in multiple resets and frustration.
Use Captains
The Captains' punch can take out most of the threatening non-boss enemies rather efficiently. Just be sure to avoid taking too much damage (although this applies less to the first game due to the ability to heal at the Dolphin). Captains can run around the sublevels of later caves to activate any traps and assess the dangers within the sublevel.
Know your enemies
Attempting a zero-death run isn't a good idea during your first shot at Pikmin (all of the games are quite difficult simply to complete, let alone without casualties), but don't senselessly sacrifice your Pikmin; rather, study what the enemies and hazards of the Pikmin games do and look for exploits, easier ways to dodge their attacks, and defeat them. Some enemy attacks can harm or kill other enemies, such as the Yellow Wollywogs "ground-pound". Many of the guides here can help you in learning about the enemies, but only by playing the game can you gain experience.