>>1306424>>1306793How do you feel on the V3's? Are they smooth, or do you feel like you're using brute force to muscle past the difficult moves? From my own experience, and working with others, it seems that many strong climbers can use that brute force to get them past any V2-4, depending on the climber. Then this leads to frustration when they try to push into higher grades and it stops working. Try out all the V4's, and try even harder stuff too if it looks like fun. You will learn new tricks that way. I sent two V6's before I sent my first V5, because they happened to play to my strengths.
As
>>1306966 said, can't really give specific tips, but my general catch-all tip is to work on your core. Also, when you watch others climb, you might notice obvious beta like drop-knees and bumping hands, but think about more subtle stuff too: Can you get your little finger securely on this hold? Should you be holding your hips closer to the wall? It could mean the difference between staying on and peeling off.
Don't feel bad about plateauing for months. The increase in difficulty from V3 to V4 is greater than V0 to V3, and so on. You're doing great for 8 months.