How do I play a lead in acoustic guitar?

Leads are much different on an acoustic guitar, for two reasons:

Lack of compression and sustain

Difficulty of bending strings

Compression and sustain are related benefits of playing through an amp with overdrive or distortion. Compression evens out the volume of notes, and enables you to use hammer ons and pull offs which sound very full. Sustain enables you to hold notes for a long time, potentially forever.

You can make up for the lack of sustain either by playing solos which simply don’t require much note length, or by picking the same note repetitively, but it’s definitely going to have a very different vibe either way. If you are trying to replicate a rock solo originally done on an electric, it’s very likely to sound quite different, no matter how good your technique.

You can accommodate the lack of compression by plucking every note, or by developing tremendous finger strength to play strong hammer ons and pull offs. I personally prefer plucking every note. I think it sounds better on acoustic.

Many acoustic solos end up with a very different overall phrasing technique than electric solos. They tend to be at least moderately fast, very rhythmic, almost all notes plucked, and tend to keep going, without leaving a lot of space. Without sustain, you definitely have less options, and it’s much more difficult to sound impressive.

While it is possible to bend strings to a full step in pitch on an acoustic guitar, it takes quite a bit of effort, and you may have real trouble reaching that note on the heavier strings. I personally don’t usually try to bend notes this much on an acoustic, but prefer to slide up or down to the note instead. Also, you may find yourself breaking strings if you try to bend them too much.

There are guitarists who specialize in playing leads on acoustic, and they are generally people with extremely developed picking skills, such as Al di Meola and a variety of bluegrass players such as Bryan Sutton, one of my favorite players. If you generally are an electric player, you might be surprised how difficult it is to solo on an acoustic like Al and Bryan do, because they generally pluck every note, and play fast, which are pretty much required for an impressive acoustic solo. Electric players are used to using a lot of hammer ons and pull offs to generate speed, but these techniques generally will not sound so great on an acoustic, which has no compression effect, compared to a lead played through an overdriven amplifier.

If you want to play lead rock guitar, I think you should consider getting an electric guitar. I definitely think it’s worth it.

 You can do this with a plectrum. In this case, developing a proper picking technique is important and a teacher can help you with this. You can practice exercises for the left hand like trills(repeated hammer on and pull off) with all finger combinations as well as picking hand exercises. Again, a teacher can guide you with these things.

Also, you need to be familiar with scales and how to use them over a chord progression. Also, techniques like slide, vibrato, hammer-on, pull-off, and harmonics will add greater expressiveness and variation to your playing.