The first and often biggest mistake is registering on the very first app you hear about from friends or ads. Every platform has its own specific audience and unspoken rules. For example, some apps are designed exclusively for quick one-night stands, and finding someone to build a family with there will be extremely difficult.
If your goal is a long-term relationship, pay attention to sites that require detailed profile completion or taking psychological compatibility tests. Such platforms automatically filter out those who are not ready to invest time and effort, leaving people with serious intentions.
Additionally, pay attention to the functionality. Platforms where it's impossible to message without a mutual like are usually more comfortable, as they protect against unwanted spam. Take the time to read reviews about different sites to choose the tool that fits your goals.