I was thinking about the speed that full use of shortcuts brought to ChemDraw in Monday’s video, and decided to explore Microsoft Word a little.  I already use the subscript/superscript hotkeys (Ctrl+[-]  and Ctrl+Shift+[-], respectively), but every time I want to insert a Greek letter I go through a song and dance with the symbol dialogue.
However, underneath every symbol is a brief code that calls it up.  As an example, type in 203D and press Alt+x for an interrobang‽  Below are some of the more useful symbols I came across.

Greek Letters
03B1 α
03B2 β
03B3 γ
03B4 δ
2206 ∆
03B5 ε
00B5 µ 0181  OR 03BC μ
Special Characters
00B0 °  or Alt plus 0176
2013 – or Ctrl and Num- keys (En dash)
2014 — or Ctrl, Alt and Num- keys
2020 † or Alt plus 0134
2021 ‡ or Alt plus 0135

Equation Symbols
00B1 ± or Alt plus 0177
2248 ≈
2260 ≠
2264 ≤
2265 ≥

21FF ⇿
2194 ↔
21CB ⇋
21CC ⇌

Alt+[+]  – Instant insert equation dialogue.

If that wasn’t cool enough, from this reddit thread:

File → Options → Proofing → Autocorrect Options → Enable Math Autocorrect

This opens up autocorrect options useful for chemists/researchers.  \alpha now inserts α, \degree does what you’d expect, and there’s hundreds more.  Custom autocorrects can be added for equilibrium arrows or whatever else ails you.