3) Simple phrases that you say a lot.
Phrase: good morning, thank you, be right back, let me know
Shortcut: gm, ty, brb, lmk
Use "gm" for good morning, "brb" for be right back, "ty" for thank you, "hbu" for how about you. The person on the other end will feel like you put more effort into the conversation if you send them more than basic acronyms. I also have the entire lyrics to "Never Gonna Give You Up" by Rick Astley in a Text Replacement because I like to Rickroll my friends.
4) Email addresses, phone numbers, Instagram usernames.
Phrase: email@example.com, +1 (123) 555-4567, @scoochcase
Shortcut: @email, @phone, @ig
Put your personal email address, work email address, personal phone, Instagram username, or anything that you type out often. I like to use "@email" as the Shortcut and my email address as the Phrase so that i never mistype my email address again. "@phone" for my phone number with country code and area code.
What's so beautiful about this hack is that there are TONS of ways to use it. Get creative and ask yourself, "What do I type out repeatedly?" Hope you get some use out of it!