<p>The surfaces of my printed parts using PLA plastic look rough and uneven.</p>

<p>Would changing filament to a better one make any difference?</p>

<p>If not, what kind of methods can I use to achieve a smoother finish for my for 3D-printed objects?</p>

It is called
Acetone Finishing
Basically the 3D printed part stays in acetone vapor and the outer shell turns to smooth surface. I have heard that it works better with ABS.
This article shows how
with videos
:
(
Acetone Finishing on PLA
- dead link).
New link:
Acetone Finishing on PLA