to tune my guitar by ear, im ok at eat like i can easily pin point wat string isnt in tune but how can i get better at tuning standard tuning just by ear.
just get familiar with what "in tune" sounds like, and get familiar with the different notes, and just memorize them
This is an example of how I do it. Or used to do it anyway.

I would play the an F note on the bottom E-string and I would be able to see if the E-string is in tune. the reasn I played the F note becuase I love Nirvana and the beginning chord on SLTS is F. It's kinda recognising the note really. But yeah simple as really. So basically just find a note that you'd be able to recognise from a song and play it and if it doesn't sound right then just tune the string until it sounds right. It's a bit wierd but it works. I don't need to do that anymore but meh it worked for me anyway.

The best way is to tune your 6th string (low E) to a piano, tuning fork or downloaded mp3 and use the 5th fret method:

1) After you tune the 6th string you fret it at the 5th fret against the open 5th string (A) until they sound the same.

2) Fret your newly tuned 5th string at the 5th fret in order to tune your 4th string (D)

3) Use the 5th fret again on the 4th string (D) in order to tune your 3rd string (G)

4) on your 3rd string (G) you need to use the 4th fret in order to tune the 2nd string (B)

5) Fret your 2nd string (B) at the 5th fret in order to tune your 1st string (E)

I'll post a link to a downloadable mp3 of a tuned 6th string if you want me to... you can probably google it quicker than that though.

nah whistler knows what im talking about and side effect. i have an electric tuner so i can tune using it, but for ear i can normally tell if i play C chord and everythings s-word i know something is outa tune, im curious really cause i got new strings and im still working them in so like every ten minutes their outa tune. and im like if i tune by ear in like ten seconds that would save me time.i just really need to memorize it.
Ear tuning comes naturally and is not something you can be taught to do. Well, technically you can be taught the open string notes but when it comes to fretted notes you won't be able to recognize them unless you're gifted in that area. Bottom line... your guitar sounds off it needs to be tuned.