Identify the bottleneck before spending
Every free-to-play strategy game has one resource that gates progress at any given time — usually a hero upgrade material or a building time. Check which task is actually blocked and spend towards that, not towards the shop's featured item.
Concentrate, do not spread
A team of five maxed units beats fifteen half-levelled ones in nearly every system of this type, because most modes scale to your strongest squad. Choose the units the game gives you most consistently and commit to them.
Time gates are the real cost
Upgrade timers are what these games sell shortcuts for. Queue long upgrades before you log off so they run while you sleep, and never let a build slot sit idle — an idle slot is the most expensive thing in the game.
Events over steady grinding
Recurring events usually pay several times the rate of ordinary play for the same actions. Save consumable resources — energy, speed-ups, summon currency — for events that reward their use rather than spending them the moment you have them.
Join an active group early
Clans, alliances and guilds provide free resources, reinforcement and event rewards. The difference between an active and a dead alliance is larger than the difference between paying and not paying. Look for one that clears its group events.
Read the in-app purchase note
The store page lists whether in-app purchases exist. If they do, set a budget before you start and decide what you are buying — usually a one-time value pack rather than a repeating currency drip.
Clash Royale: one deck, fully levelled
Upgrade one deck you understand rather than chasing the meta every season. Card levels are permanent; balance changes are not. Keep one or two flexible slots and keep the rest stable.
When to stop
These games are designed for daily sessions, not marathons. Log in, collect, queue upgrades, clear the event, log out. Progress that depends on timers cannot be forced by playing longer.