If you are an inexperienced guitar player, and aspire to play in duos, trios or full bands, it’s important that you get together to play with other musicians as soon as you’re able. I can’t stress the importance of this enough.
Most guitar players feel they need to reach some level of proficiency before they get together with others. That’s true, but don’t set the bar too high initially. If you can get through a song strumming the chords without interrupting the rhythm, you’re ready enough to experience playing with other musicians.
By playing with another person, you learn about staying in time together, transitioning from section to section together, and controlling your volume so that you’re balanced. You develop a visceral sense of what it means to perform in a group. You learn how to keep track of all things you think about while performing. That has to be experienced first-hand.
As you play more, the areas of your playing that need attention will become more and more obvious and that will guide you in your practice.
If you’re fortunate enough to get together with someone with more experience, do that. If you have a practice buddy who plays at about the same level as you, that’s OK, too. Just find a person or circle of people you can play with.