Playing by ear

This should get you started:

http://www.justinguitar.com/html/transcribing.html

Su

Jeff, I sometimes have this problem too. the good thing is you can get the chord progression.

What I usually do is sit wit hthe guitar and try strumming a chord continually until I hear it is right with the song. Or sometimes a G. or A or D. usually find out what key the song is in then.
Then just fart about wit hthe chords within that key.
If you know the song very well then it makes it easier.

But also remember that sometimes bands tune down as well as tuning up on their guitar so if your guitar is tuned in concert pitch then ye might not get any of your chords sounding like the song you are trying to work out.

I had a lot of trouble years ago when I was learning bass lines for Guns 'n' roses songs. they tune down, just like Jimmy hendrix. When I finally bought the bass line book, that told me they tuned down. after I tuned down I never had much bother whith the bass lines.

Hope that helps, even if a wee bit

Ken

If you know what key it's in, you should at all times know the IV and the V for that key.  Odds are pretty high they'll be in there someplace.  It would also help to know each of the triadic chords for the entire key.   Learning the major scales is eminently useful for this.

Hey there Jeff, I too am self taught and what I can tell you is that figuring out tunes is an ability that one gets better at like any thing else the more you practice at the easier it becomes. What I do is use bar chords to help find what fits while the tune is being played and then if you choose to swich them over to open chords, Learning how to play bar chords would be my first step in your case if you want my opinion.

Learning scales is kind of like learning algebra.  You sit there wondering how you're ever going to use this stuff and then one day you've got the answer in front of you and you need to figure out what the question was and all of a sudden you're pleased that you did the work. 

It's possible to play without scales, but a lot harder to figure things out.  I've been a bass player most of my life, but only just started to work scales a couple of years ago and it's been tremendously helpful.  I wish I had done it twenty years ago. 

- Zurf

When they talk about the IV and the V, they're talking about the fourth and fifth note of the scale in which key you're playing in.

So if you know which key you're in, play that scale, and the 4th and 5th notes you play are the related IV and V chords.

Example, in C.

C D E F G A B C

The 4th and 5th notes of the C major scale are F and G.  So if you were playing in the key of C, you could count on F and G major chords showing up. 

Same with any other major key.  In fact, almost all common chord progressions can be derived this way.

Jeff, you have a lot of information now and this makes me happy. It is difficult to add more comment. I learned a lot, trying to play along with songs, this helped me a lot.
Zurf, your answer is great. Reading it, I get scared. All those scales. I am not a guitar hero, but I play pretty good, until I read, see, and hear other people playing. In a way, I am lazy too, skipping a lot of very interesting tips, like blues scales. Tabs: same thing.
Even playing pretty good, I notice that 90% are playing better.
- Fingerpicking: I try, and I use it more and more ONLY a few seconds.
- What term is used when you try to play "fingerpicking style" using a pick?
- Am I lost, because I developed a particular style, like strumming, followed by blocking chords, or strumming starting with the big E string to the little E string? This strumming is going once or twice, down, and going back, I use often 2 or 3 strings, providing me a similar sound as a power chord.