Volatility, theme and budget — three key factors
The most important question when choosing a slot is — do you want to win small amounts often, or wait longer for a bigger win? That is the essence of volatility. Low-volatility games pay out smaller prizes more frequently; high-volatility games require more patience but the wins can be larger.
RTP (Return to Player) is the theoretical figure for how much a game pays back over the long run. For example, PG Soft's Fortune Mouse has a maximum RTP of 96.96%, and Mahjong Ways 2 has a maximum RTP of 96.95% — but this is not guaranteed in every session; it is an average across a large number of spins.
Choosing a theme is not something to overlook either. From Asian mythology to football, fishing to adventure — playing a game with a theme you enjoy keeps you more focused and entertained. From a responsible gaming standpoint, setting a budget is also important — decide how much you are willing to spend before each session and do not go beyond that limit.