I've been practicing No Starworld but when I try to do FOI2 Yoshi clip I either miss it completely or get stuck Inside a block where I can only go up and no other direction. How can I avoid this?

When you clip into the corner, hold down + towards the direction you want to clip (usually left) and press A
Actually getting into the corner is purely timing, but making the clip through the wall without being kicked out is subpixel dependent