Well...I got this game when I was like 10 or 11...and somehow I managed to play it for like 7 years and accomplish nothing...so my mistake would be not reading the instructions or even the back of the box to figure out I could get married, go to festivals, or for some reason be friends with people since everyone had like 1 heart...
Another mistake was not brushing my horse (must have missed the part when someone told me to do it) and it was taken away from me
Luckily I hadn't saved so I'm now stuck forever on the day before my beloved horsey was taken from me...and it was at 3 hearts like the post above
So recently I made a new file (saving the old one for a reminder of how not
to play harvest moon and I began again though I'm still in spring and havent played it much.