It’s actually very trivial for a user to get the Windows 10 update without having to wait for their reservation from microsoft.
To do so simply navigate to this page and follow the prompts.
Most Likely you will want to Download the 64 Bit Version. Once you have done so it will as you to select the correct Windows Option. Be sure to do this CORRECTLY. You can only update to the same version as you currently have. If you have Windows 8 Home then you need to stick with Home. Windows 8 Pro can upgrade to Pro. There are also options for Windows N or KN. If you’re in the US these wont apply to you. They are special versions of Windows because various countries have forced Microsoft to remove features from Windows. Just get the normal Windows 8 Pro or Home and you’re off!