Strumming patterns you’ll just develop a feel for. You can practice that against your knee while just casually listening to the song. An exercise you can do for this is to practice three-chord rock songs. A LOT of songs are written with a progression of A, D, Em. Two examples off the top of my head are Louie Louie and Wild Thing. The difference between them is the rhythm.

I’ve been playing guitar for 25 years now, I do know how to read sheet music from band class in school, but I’ve never combined those two skills. I’ve been handed sheet music for Piano or some other part that had guitar chords over it, and a lot of the more intricate pieces I know I learned via tablature. The nice thing about tabs is they can be fairly easily made with ASCII.

You want a fairly easy way to make yourself sound WAY more impressive? If you’re comfortable strumming chords, you can start picking individual strings instead. I like to use House of the Rising Sun as an example for this. The chord progression is Am, C, D, F, Am, E, Am, E. You can just strum along with a fairly simple rhythm, but, instead of strumming all strings, pick them individually as found in this tab. Your fret hand still does the exact same thing, but your pick hand does a little bit more. This song is a good introduction to this because your pick mostly goes “down” (physically toward the floor toward the higher strings) then back up a couple. It’s also a fairly easy introduction to finger picking.

Fun fact about House of the Rising Sun: It’s in common meter. Which means you can swap the lyrics for other common meter songs into it to interesting effect. Many of Emily Dickenson’s poems are in common meter. So is Amazing Grace and the theme tune of Gilligan’s Island. You can have a lot of fun mixing and matching lyrics with melodies. It’s a fun trick to have in your repertoire when you’re passed a guitar at a bonfire or something.

In my opinion, outside of some specific songs, strumming pattern will end up being your personal touch. You’ll strum in a certain way, and as long as the chord progression is right, it’ll sound correct. More attention will be paid when you’re playing individual notes. The rest is really up to you, and that’s probably going to seem frustrating at first, but it’s really liberating once you’ve been playing for a while.

My personal recommendation is to learn stairway to heaven by Led Zeppelin in its entirety. There are a lot of unusual chords, barre chords, techniques, etc in that one song. Additionally, you’ll need to either practice hybrid picking or finger picking. When you finally learn it completely, almost any other song will seem easy to learn. I learned it in my first few months playing guitar (20 years ago) and I’m so happy that i did, i still find it pretty easy to pick up most other songs, but also find myself playing it from time to time.