Please help me make my handwriting more legible

Soon I'll be having mock exams and I still have 5 months until my GCSEs and all my teachers have told me that my handwriting is hard to read.

Where can I begin to improve?

I also noticed that writing with pencil is way more comfortable for me but I haven't really found a good flowing pen to write with that feels right. I wrote with some other pens for reference but the first one is the one I usually use. Are there any good pens that feel similar to pencil?

(Sorry for any mistakes, English isn't my first language)