If you’re on a Mac (US KB layout), here’s a quick guide to common diacriticals (no need to remember any special codes or reference the chart if you internalize these).
[NB: you press alt+letter to get the diacritical mark (it will be underlined to indicate it is waiting to assign it to the next letter you press), and then strike the letter you want it to apply to. For instance, alt+e (then) e = é whereas alt+e (then) a = á.]
alt+e = ´
alt+i = ˆ
alt+u = ¨
alt+=
alt+n = ˜
alt+c = ç
And for you Latin fans out there:
alt+q = œ
alt+’ = æ
Another useful one is alt+g = ©
Moral of the story, try pressing alt+[any key] and also try it in combination with the shift key. You’ll find that there are many special characters that do not require any copy+pasting or lookup tables. Lastly, there is no need to download special apps if you’re on a mac. Just tell the mac in preferences to show the keyboard layout switcher up in the task bar by the clock. Then, if you ever need it for the more obscure marks, click the symbol and select “Show Emoji & Symbols” and the character viewer that is built in pops up. There is a “Latin” subsection with every marking known to mankind.
Julian’s comment about the limitations of various fonts is very critical as well.
