Stardew Valley/Phases of play

Early Game
In the early game, you have very little money and your energy runs out very rapidly. You’ll get fitter as time goes on (as your skill levels increase) but it will take time.

In this phase of the game it pays to tend plants until mid morning, then go spend the rest of the day walking around. Foraging takes no energy and you find edible/saleable items. In your second season the Spa opens up and you can visit this to rebuild your energy. If you get enough extra energy from foraging or the Spa, use your extra time for clearing, mining, or fishing.

Few items besides seeds may be affordable. Seeds are likely to be your best investment anyway.

There are several events that introduce new elements of the game, and it makes sense to pursue each one for a day when it comes up.

Mid game
Energy is still a significant constraint but you will also be finding that you could use more hours in the day. You will be wanting to do watering, mining, tending animals, organising building upgrades, chopping wood, upgrading tools, fishing - and quests. Quite a wide variety of quests - two day tasks posted outside Pierre’s, and open-time-frame quests that come by mail, and quests that are triggered by related accomplishments - and the Community Center, which provides an over-arching goal and some very significant interim rewards.

Money is an issue, but you should be earning a decent chunk of it, so that you have tactical decisions to make about which things you want to spend your money on.

Later game
Money is no longer an issue. By the time you have completed the Community Centre, you may have a very substantial income. You should also have plenty of food, meaning that energy is no longer a concern for you. Your chief constraint is time - you still want to get home by 2am so that you don’t collapse. Then again, collapsing from exhaustion only costs you 1000 gp - maybe you needn’t care any more!

At this point your goals are likely to revolve around collecting star drops (which means completing collections, worthwhile in their own right) and optimising and automating your farm. Milking cows and feeding cheese presses, once such a profitable enterprise, starts to become more labour than you want to put in. You may have the resources to build more buildings than your farm will fit. You may gradually acquire enough iridium sprinklers to put your whole farm under cultivation - the hard parts are planting it all and harvesting.

Grandpa’s spirit will come by on day 1 of year 3, and praise your progress; if you have achieved enough, his shrine will release an iridium-generating statue, which is a real asset to the subsequent development of your farm. If you haven’t done quite that well, no worries - you can offer a diamond to the shrine later when you’ve done more. You probably have 20 by then.

There is a whole new class of buildings that open up after you complete a quest for the wizard - teleporters and Junimo harvesting huts - and these buildings cost vastly more than the dwellings on the Community Centre sequence; so there is a substantial savings phase, in which you have more money coming in than you can spend on the mid-game dwellings, but you’ll have to save for a while in order to get the late game ones.

Getting the most money for your labor is often done by planting slow growing, expensive fruits and then processing them into wine, and aging the best of it to iridium quality in your Cellar. This way you don’t need to touch the items much to get your money. Pigs gathering truffles are also pretty effective.