A good spot
Find the most optimal spot in your home. Wi-Fi signals have trouble getting through certain barriers such as walls or heavy appliances. Find a spot in your home where you can get the most strength out of your modem.
Update your modem's firmware. Firmware is software that controls a certain piece of hardware. On older modems, it's likely the maker has a firmware update that will improve its operation.
Look for apps that drain your modem's power. Most modems allow you to decide which apps you want to prioritize to prevent one from taking over your Wi-Fi bandwidth while you are working on an important project.
Change the channels on your modem. Wi-Fi uses radio frequencies just like walkie-talkies. If a neighbor is using your same frequency it can interrupt your service. Try out different channels to find one that works best.
Extend your range
Consider buying a Wi-Fi range extender or mesh extender to aid in dead zones in your home. Regular extenders create a new network from your existing one, forcing you to change networks as you move around. Mesh extenders use the same network and can share data more efficiently.