These will use a form of ‘bod’ that many will not have come across in the course yet (disclaimer so as not to panic people!)
The more I learn about it, the more I like it. = Po fwyaf y bydda’n dysgu amdano, y mwyaf dwi’n ei hoffi / licio.
The less I see of him, the better. = Gorau po leia y gwela i ohono.
The more I earn, the less spare time I have. = Po fwya dwi’n ei ennill, y lleia o amser sbâr sydd gen i.
However, that can sound a bit literary, so people would understand you if you were to say them with a more direct translation…
Y mwy dwi’n dysgu amdano, y fwy dwi’n hoffi / licio fe / fo
Y llai dwi’n gweld ohono, y gorau
Y mwy dwi’n ennill, y llai amser sbâr sy gen i