I read that the most common letters for 5 letter words are SEAORILTNDUC. So if I'm not playing hard mode I've been guessing AROSE>TUNIC for guesses one an two and it helps narrow the words down a lot.
I guess letter placement is important too, but I haven't thought about that much. I saw someone saying that ARIES was a better first word for that, I'll have to give it a try.
RSTLNE baby.