Three string chords

I've been working on playing Stairway to Heaven based on the tabs shown on http://home.arcor.de/crazydawg/tabs.html. There is a section of the song that goes between strumming 3 strings ans strumming 4 strings. I'm pretty new at this, and I've been trying to do it by muting the A when a three string chord is called for. Are there any other techniques for this?

Control your strum by not striking the A string at all.

Rep? =P

It depends on the type of strum called for and the tuning that you're using.

If you're tuned GCEA you can run down the top strings with your thumb and stop (bring your finger to a rest) on the A string, you could strum UP from the E string, if you have enough control during your strum you could just strum it and pull away before hitting that A, or just mute the A and strum all 4.

If you're tuned ADF#B you pretty much have the same options, just in the opposite direction.

Another alternative would be to find a different way to hold the chord, one that puts the melody note on the last string that you'll be strumming.

^^^ One of the parts the OP speaks of contains the following:

|-------|
|-0-2-3-|
|-2-2-2-|
|-2-2-2-|

I just use my thumb on this part and stop before striking the A string. Besides, it doesn't matter too much if you strike the A string because 2nd fret on the G string is A anyway; although, if you're using a low G tuning, it would sound different.

Alternatively, you could do this as well:

|-0-0-0-|
|-0-2-3-|
|-2-2-2-|
|-------|

Thanks for the advice I think I'm gonna try the thumb only strum thing Super, I've noticed that while playing this song if I down stroke with my thumb at just the right angle the notes sing out in a really pretty way.