My Level 10 Game Strategy
As a long-time SimCity player, the first thing I did when I started playing was to build my city's population, expecting most of my city revenue to come from taxes. If you haven't learned already, taxes decline (per capita) as population grows, so taxes didn't really contribute much toward the growth. Anyway, I've built this city to 1mil pop so far, unlocked everything (I think) and am producing enough stuff to sell, but if I had it to do over again, I'd have done it differently.
And I have done it differently. Though I could earn enough coin at level 40-something, I couldn't find enough of what I needed in the TradeHQ to expand my city's land or storage. A second city on another FB account at a lower level made it easier to shop for those rare expansion materials. It has actually done it so well, that it is free to expand itself, using what I've learned from the first time through.
1) Do NOT go (much) past level 10, before you expand your storage and city landscape, or you might never be able to get enough parts to do so. The final storage expansion requires 25 of each item, and the land expansions cost up to 20 of each. More frustrating than not having the money to buy something is having the money, and still not being able to buy for other reasons. Take your time, and build your population in a dense area while you prepare to expand
2) Upgrade residences instead of building new plots, to maximize population vs expenses. I have 17 plots, all fully upgraded, and I'm just below the upgrade to level 11. With Parks, Education, and Transportation bonuses, those 17 plots now serve over 124k residents. Parks got me over 50k (the 8k 25% one). The Cargo Ship slowly provided enough keys to get the population over the 90k needed to unlock Dr. Vu, and then you can really make a lot of keys, if you're already crafting.
3) You make money from crafting, primarily. Expand your queues enough to keep them active as much as possible, and sell the excess in the market, if the game doesn't make good enough offers via the coin bubbles. NEVER sell anything for less than the maximum (unless it's to yourself, heh)
4) Smart trading can add some coin to your account. As long as you're not finding what you actually need, you can offset the loss of time by buying up the most expensive but under-priced items you find listed by others, and reselling them. Always buy everything Daniel sells, except maybe metal or wood.
5) Earn as many keys as you can before leveling up. Rebuilding demands materials, and they just get more expensive and time-consuming as you level. So do as much as you can at a low level. The guide I've linked to below estimates you'll need about 1200 of them. Wouldn't you rather pay for them with nails and planks than couches and burgers? 😉
Check this Layout Guide for an idea of how much you might need in resources (coin, keys, etc) before continuing with your leveling up.