How can I make my engineering MSc dissertation look professional?
It is important to use format templates i.e. do not format a heading as 12pt and bold but format it as "heading 1" (and change the properties of a heading 1 as you like). Also for the flow-text and figure captions use the Word in-build features instead of doing it manually. By this way you can change the whole document within seconds if you are unhappy with the layout. And yes, you can make your word document look exactly like a TeX this way. In my opinion learning TeX is not worth it (I wrote my MSc and PhD thesis in TeX) as you will hardly need it every again (I never used it again after my PhD) as any type of later collaborative work will most likely be done in Word.
Word is very mighty if you use it correctly but few people use it that way.