1. Make sure your keyboard is in NumLock mode.
2. Hold down the ALT key and enter the number on the numeric keypad. (Note that many laptops have a blue FN key that changes a set of keys, also with blue numbers on them and usually in the 7-8-9-U-I-O area, into a numeric keypad.)

for ☺ 1
for ☻ 2
for ♥ 3 <===
for ♦ 4
for ♣ 5
for ♠ 6
for • 7
for ◘ 8
for ○ 9
for ◙ 10
for ♂ 11
for ♀ 12
for ♪ 13
for ♫ 14
for ☼ 15
for ► 16
for ◄ 17
for ↕ 18
for ‼ 19
for ¶ 20
for § 21
for ▬ 22
for ↨ 23
for ↑ 24
for ↓ 25
for → 26
for ← 27
for ∟ 28
for ↔ 29
for ▲ 30
for ▼ 31