Before a spin
Check the total stake shown for one spin. On games with selectable lines or ways to win, the displayed total matters more than the value attached to a single line. Open the help or paytable before you play: it explains qualifying symbol combinations, feature rules and the value of any prizes.
The mechanics are worth knowing before money is committed. That leaves you free to decide whether the game suits your own limit and time.
Random outcome, not a pattern
The Gambling Commission distinguishes fully random machines from compensated machines. Fully random games keep the chance of each outcome constant, while a compensated game may vary the chance of a prize in response to earlier results. In both cases, the game information, not a recent result, is the proper source for understanding the machine you are about to use.
A clear explanation is not an instruction to play. It is a reason to avoid guessing.
RTP in context
Return to player, or RTP, is a long-run percentage rather than a promise about a visit. The UK Gambling Commission explains that it is measured over many plays; it does not mean that a £1 stake returns a fixed amount in one session. Set a money limit and a stopping time before you begin.
If a visit still appeals after reading the rules, ask the venue about current entry, access and session details before travel. A clear plan leaves room to change your mind.
If the machine gives an RTP figure, treat it as a long-run measure across many plays, not a prediction for your own session.