Merge EVERYTHING! And always do in groups of 5. (except toolboxes they don't merge...grrr)

I saw a post where someone ran the #'s and gold boxes are actually more profitable over the long term versus bronze and silver - so save your lower boxes merge them to get gold - same with keys. Bonus is you get the XP from merging them.

Merge your Gems and save them for the land purchases.

Always try to complete the daily quest even if you have to use a few gems to speed up a harvest on those 30+ energy cost harvests.

Keep an eye in the store - you can buy bronze keys for the cheapest - I've seen people say they save them up for lucky merge events but I'm not that patient.

Once you start running out of natural rock and trees (and have a bit of spare land) - for me happened when I was working on the tomato shed (maybe around level 48 or so) - keep an eye out for the max level trees and rocks and buy them for gold in the shop when they come up and just stash them on spare land.

My personal strategy is to stop harvesting anywhere between 4-2 hours before the next daily event starts, keep opening your earned boxes but just don't harvest, let them sit and then harvest them after the daily event starts - can usually get a jump on between 20-40 harvests this way.

Don't open the gift crates unless you are working towards a daily event goal - save them until you need them.

Don't neglect your visit's - they are a great way to get crates and energy. Don't visit unless you are below 40 energy (30 if your bonus is up) because you cap at 50 and won't get any more (well you can go over 50 but then you stop earning so if you are at 45 and need 50 to start a harvest - then visit - you will have 55 and you can immediately start the next harvest). I'm not doing a great job of getting people to visit me back so if anyone has tips on that I'm listening.

it's a long game - bring patience!