A better title might be how to learn to play the guitar.

Practicing 5 minutes a day versus 60 minutes a week will produce much better results.

When learning a new chords, riif, or new fingerings always play it very slowly without any errors. If you make an error and continue to make the error you will never get it right. Playing the guitar is a brain to muscle action and once your brain learns it wrong you will waste a lot of time trying to get it right and it will get frustrating, always start slowly.

Learning Riffs or Songs

Learn 3-5 measures at a time, the fewer the faster you will grasp them. Go slow and accurate to learn new riffs is always fun as you will see in the future. Play a riff right about three times really slowly today and do the same thing tomorrow and the next day. By playing it slowly and only a few times each day you brain is learning it and by the end of the week you will be able to play it much faster and accurately and you only practiced that lick for about a minute a day.

Playing Chords

When moving a chord shape up the neck, do not slide it, lift hand and damp strings and play new chord. You do not want any sliding or string buzz.

When playing a chord play the chord as close to the frets as possible so the fingers actually pinches the string to the fret.

Strumming a Chord

When strumming a chord do it forcefully so the pick does not make a plastic sound, you should only hear the chord and not the pick.
When practicing, turn you tone control all the way up and the treble on the amp all the way up so you can hear the mistakes and correct them.

Right Hand Technique

Keep your right hand in a loose fist. Don't get into the habit of resting you pinky on top of the guitar.
You can rest you palm on the bridge of the guitar to dampen the strings but your hand should always be above the guitar when strumming.

Plectrum / Pick techniques

Use pick to play and when you play do not make pick noise, if you hear the pick flapping as you strum use a thicker pick. You may want to get a thin, medium and thick pick and see which one you like the best.

Playing with Your Right Fingers

If you use your fingers and not pick the sound is better, but only do this once you can play with a pick. Trying to learn to strum and use your fingers when you just beginning can make for some very awkward sounds and you will have to learn timing, strumming techniques, and fingering evenness all at the same time.

Once you can strum with a pick start using your pick and your fingers together, use your right hand's lower three fingers for strings 1-2-3 or 2-3-4 and pick the top two strings with the pick. This is the best method of playing since you will be the most flexible and the sound from your fingers will be very clean.