One of the best parts of being a musician is to participate in jam sessions. It is here that you make music with others, stretch out your skills, and grow. When you have songs that you’re comfortable playing, and can learn what others are bringing in you are ready to jam.
You’ll need to communicate musically with others. This means having an ability to teach (output) as well as understanding what they show you (input). When bringing in a song you’ll be expected to demonstrate the melody and main riffs of the song. You’ll need to play the chords and know the structure of the song.
In addition to knowing major, minor, and 7th chords in the open position, you should be able to play bar chord forms. To play “lead guitar” you must know the pentatonic scales and even better if you know major and minor scales. Having a facility to play these scales, along with a good ear enables you to pick up lead lines, riffs, and improvise over chord changes.
Beginning players often strive to make the song sound exactly like the recording, but be flexible on this point. If needed simplify your approach. You might need to slow the tempo, or play fewer verses. The point is the sooner you play, the more time you have to experience making music.
To prepare think of specific goals you’d like to achieve. You may want to play a new song, exercise a particular technique, a new riff, new chords. As a format go around a circle with each player introducing a song. I suggest having three song ideas to add to the circle. When it’s time to play have fun, let your creative juices flow, and you may develop musical friendships that enrich your life for many years.