This is probably blindingly obvious to long-term Windows people, but switchers/multi-platformers like me may well be unaware.
Back when I last used Windows, (not entirely true — I would dual-boot Windows 7 for playing games, but that required so little paying attention to Windows itself it hardly counts) I’d been using Alt codes or the character map to make accents and diacriticals. Switching over to the Mac, the use of dead keys sped things up considerably. Pressing option+e would put an acute accent on the next letter (if valid in the character set), option+u would apply an umlaut and so on.
Turns out I can do this in Windows too and had been able to long before I moved to Mac. One must have UK International keyboard as your input device though (Control Panel – Clock, Language and Region – Change Input Methods on 8.1). When this is the case, you can use Alt Gr/right Alt key plus the dead keys before typing the relevant letter:
AltGr+2 = umlaut - ü AltGr+6 = circumflex - ô AltGr+# = tilde - ñ AltGr+'(apostrophe) = acute accent - é `(backquote) = grave accent - è (no Alt Gr press) AltGr+c = c cedilla (won't modify an s) - ç
Frustratingly, the US International layout means you can gain similar access to things like thorn Þ or the copyright symbol © without resorting to numerical codes, but the UK version does not.
Might be time to create a hybrid layout that has the UK characters in the correct place, but with the US extensions.
OS X does do this better.