98% of the time most technology issues can be fixed by a simple power cycle of your equipment. Try unplugging it from power waiting five to ten seconds, then plugging it back in.
I have to ask people constantly at work if they have restarted their device when they ask me questions. Like I said, the majority of the time that fixes it.
If the power cycle doesn't work, you are going to want to try to gain access to the device that is supplying your WiFi. I am assuming your question is about your home wifi and not wifi you are trying to get in a public location.
If you are able to gain access to your wifi device, check to make sure all of the settings are okay in there. You should see an area where it tells you want the radios are doing and you should also see an area where it tells you if you are connected to the Internet. This would usually be through cable modem or DSL or whatever service you subscribe to. If you don't see any incoming signal, try restarting that device as well.
If none of those things have obvious solutions, you might be looking at having to replace the wireless router. They do sometimes go bad over time.
Generally, I try to troubleshoot it myself.
Reboot your router first, that fixes the problem more often than not.
If that doesn't work. I check the wire connections, power source, drivers for issues.
If it gets real bad, just call your ISP. Whether or not you have an ISP that will be able to painlessly help you, is another story.
Hack into someone else’s WiFi.
And if that’s not possible: sit in a dark corner and gently weep.
I reboot it
If that doesn't work I troubleshoot it
If that doesn't work I resort to my wired connections while cursing the ether that causes wireless signals to not work
If that doesn't work I tether my cell phone
If that doesn't work I weep, cry, call my ISP and make sure its not on their end.
If that doesn't work I check my neighbourhood for open signals (yeah theres still a few)
If that doesn't work I decide if I want to go out to someplace with Wi-Fi
If that doesn't work I reboot it again because it should have been long enough by now. Router and modem of course.
If that doesn't work I accept the fact that I am not loved by the universe at the moment, boot up Plex and binge watch movies or TVs for a few hours while constantly glancing at my PC to see if the little network icon is again showing internet connectivity.
You can create a hot spot with your cell phone. i have done it a few times but watched a football game on my laptop through it and it cost me a fortune. I think if you are not streaming though it wouldn't be so expensive.