Make Your Fingers Their Best for Guitar

Warm ups, exercises, therapies and techniques to get your fingers their best for playing the guitar.

Steps

Warm up your hands. Do not soak them in warm water, as the callouses on your hands will be weakened by it, and your fingers will sting. Try instead holding a cup of hot coffee, tea, or using a hand warmer, or just sitting on top of them for a few minutes, if you can't find anything else.
Use warm up exercises on the fretboard. A good one for alternate picking is 1-2-3-4 ascending and 4321 descending, 5-7 ascending and 7-5 descending and moving those around. This will increase your dexterity over time and is particularly helpful with shredding.
After you have done these steps and your playing at a gig, use gloves to get you there to keep your hands warm.

Make sure the fingernails on your fretting hand are kept short at all times.
Try not to play right after a bath or shower, or washing your hands. The water makes your hands softer, which will make them sting by playing. Wait a bit after your fretting hand is exposed to water.
If you are playing at a gig, it is best to play the intro to your opening song to warm up before playing on stage.
Make sure you wash your hands before and after you play and wipe down your strings with a cloth that won't leave any lint behind (not good for the strings).

After extensive guitar playing, you may notice callouses on your fingertips. These are perfectly normal for the well practiced guitarist.
Do not do too many sets on the "grippers." If your hands start to get sore, stop and rest them.
If at any time, your finger feels very sore, stop and take a break for a bit. Eventually, you will be able to play for longer periods of time.
ONLY A BIT of methylated spirits only on the TIPS of your fingers.
Don't use soap. This will slow your hands down and make them feel funny.
"Grippers" don't actually help with guitar playing. But they may bring about tendinitis, so you may wish to avoid using them.