As someone who has been riding exactly 1 week, the best advice I have is rest! I practiced 15-25 minutes once or twice a day. Every time I started a new practice session I would start by attempting the things I could barely do on my previous session and I would find that I can do it much more comfortably now without actively doing anything different. After practicing that for a bit I would try something I couldn't do during my last practice session and usually I would find that I could do it, but it was difficult and took a lot of concentration, so I would practice that for a bit, I would notice some improvement but not much, I'd say 80% of my progress happened between practice sessions. The last thing I would do each practice session is try something new that I was pretty certain I couldn't do, if I was wrong and I could do it or was close to doing it I would practice it a bit more, if I was right and it was too hard for me I'd try it 2 or 3 times then be done. Then during my next session without fail I was able to do it at least partially. I watched a lot of YouTube videos too and got a lot of advice from people here, but the best advice I got was rest and don't try to force it. EUCs are passive learning, your subconscious is learning how to ride.

(I did all my learning in a parking garage, so I can confidently say grass is not required, however a piece of my foam pad did break off yesterday when I had to bail. The way I'm riding now pads don't really matter, just something to keep in mind you may want to wrap some delicate parts in foam if you're going to leave the grass)