The comparative usually is formed with an -er ending or the word more or less.
We need to find a better stopper for this vial.
[good changed to comparative form better with -er] We need to find a smaller stopper for this vial.
[small changed to comparative form smaller with -er]
We need to find a more tapered stopper for this vial.
[comparative with more]
We need to find a less tapered stopper for this vial.
[comparative with less]