If you are not working on your PC and instead of using a mobile to get the internet connection through your neighbour's wifi, you have three options to optimize the connection stability and strength.
Phone case- Sometimes, harder phone cases tend to block the signals of wifi. Especially when the router is already far away from your device, make sure you don’t have a cover on while using the internet. Of course, also make sure you don’t drop the phone!
Choosing the right access point can enhance your signal strength in mobile. You can install a Wifi analyser app and check which spot at your home has better point for access. You can use your device at that point or near it for a better connection then.
Old and conventional, the best method is to choose the room closest to your neighbour. This will automatically create fewer obstructions and distance, thus provide greater strength to the wifi signals.