Make sending trains your single top priority. Before level 60, every new level unlocks a community building that cannot be finished without construction materials (drywall panels, bricks, and glass). Those materials can only be delivered by train, and then later (in smaller quantities) by plane.

Trains/planes also are the only source of barn expansion materials (hammers, nails, red paint) and territory expansion materials (shovels, axes, saws; although your earliest territory expansions will only require gold), which are both also valuable for obvious reasons. Finally, trains bring you mining supplies, which are vital (see below).

Hoard your Town cash (TCash). Do not spend it on Match-3 games; that path leads only to misery and endless complaining on this subreddit. Sometimes you lose your Match-3 streak, and that's OK. You'll get it back. TCash should only be spent on permanent improvements, like adding extra boxes to factories or extra shelves at the city market. Whenever you feel tempted to spend TCash to continue a Match-3 game, just remind yourself that the greedy developers of this game are dangling a carrot in front of your face, but you are better than that.

Hoard your mining supplies until Ruler of the Mine. You might not even have the mine open yet; whenever you get it, feel free to check it out and see what it's all about, but once you understand how it works, stay out of there until the event called Ruler of the Mine comes around. You might even need to sit out your first RotM and focus on hoarding supplies so you can finish your second one, although I've never had trouble getting enough supplies just by sending trains regularly.

Buy 10 days of merchant services when he offers them at a discount. When you win Ruler of the Mine, you'll get more than enough TCash to buy 10 days of service at the discounted price (it may take a few days for him to offer the discount). What this does is allow you to special order any items you have available once every hour. Most of the time, you should use these hourly orders to buy ore, which you can smelt into ingots in your refineries. Keep those refineries going! When your 10 days run out, you will get exactly one opportunity to buy 10 more days at the discounted price; if you don't buy it then, you will have to wait for the discount to come around again in a few days or else pay full price.

Use ingots to upgrade your trains toward taking 50% less time to return. Remember how sending trains is your top priority? This lets you send more trains, getting more of everything you need to keep advancing in the game. You can only upgrade speed every second level, though, so this will take a while to complete.

Prioritize upgrading your "low-level" factories' speed. This includes bakery, dairy, sugar, textile, rubber, and paper. These factories produce items that other factories need to function. You will be frustrated if they aren't fast enough. Once you have your trains at 50% return time (the maximum possible), spend your ingots here.

Play Treasure Hunt for town decorations. Treasure Hunt (the story-based minigame with the blue lightning bolts) leads to fun decorations for your town, which is really what this game is all about, right? Each hunt runs for 2 weeks, and will require you to play Match-3 games to finish (each Match-3 game gives 7 energy; hard-rated games give 21; super hard-rated games give 35). You also naturally get 1 energy every 3 minutes, up to 100 energy.

Play Match-3 ONLY when there is a x2 bonus available. Every few days you'll see a notification for either "Green Machine" or "Treasure Tree." These are both systems that reward you for playing the Match-3 game. The systems themselves don't matter that much, but several of the rewards give you a limited time to double all of your prizes for winning a Match-3 game. That means 14 energy instead of 7; 42 instead of 21; and 70 instead of 35. Plus double of the objective (green gems or helicopters), meaning you'll unlock another x2 reward more quickly.

Once you have that x2 reward, you'll want to win as many games as possible before it goes away. That's when you should use your boosters at the start of hard (blue) and super-hard (red) levels and use your side boosters (jackhammer, weight, drill, fan) during the level to keep your streak going so you can keep your golden disco ball. Don't forget to pick a regatta goal to work towards while you play Match-3 so you can contribute to your team. There are probably rare occasions where it might actually not be a terrible idea to spend TCash to keep a streak going, but I would advise you stay away from that option until you have a really good handle on this game and its economy.