Great software is free. Get Macrium Reflect Free v.7 [8 is (hopefully) coming] at macrium[.]com/reflectfree
You'll need a place to store your backups. Depending on how big your backup archive is, which depends on how much stuff you're backing up, the cheapest storage is a small SSD, with ~120 GB frequently on sale for $18-$20. From a quick look today:
amazon[.]com/Kingston-120GB-Solid-SA400S37-120G/dp/B01N6JQS8C?ref_=Oct_s9_apbd_oup_hd_bw_b1PRaOp&pf_rd_r=ZD04STECN1CYX1STXG4A&pf_rd_p=1b1be201-7bd6-58eb-a5b9-a220df2ae35b&pf_rd_s=merchandised-search-10&pf_rd_t=BROWSE&pf_rd_i=1292116011
If you want that drive to be external [USB] rather than inside the case, a housing can typically be found on sale for around $5. From a Very quick look today:
amazon[.]com/ORICO-USB3-0-External-Enclosure-Supported/dp/B01M08LCXW/ref=sr_1_28?_encoding=UTF8&c=ts&dchild=1&keywords=Computer+Hard+Drive+Accessories&qid=1622759632&s=pc&sr=1-28&ts_id=11548952011
To go to a larger amount of storage, the most reliable is a traditional hard disk.
amazon[.]com/Seagate-BarraCuda-Internal-Drive-3-5-Inch/dp/B07H2RR55Q/ref=sr_1_3?_encoding=UTF8&c=ts&dchild=1&keywords=Internal+Hard+Drives&qid=1622759507&s=pc&sr=1-3&ts_id=1254762011
If you want to make a conventional hard disk external, there's an added concern: heat. An external housing with a fan is harder to find and more expensive -- an alternative is a hard drive dock. There is a model with a fan where the hard disk lays down, but the fan requires some re-working -- I have one. My preferred solution is a traditional dock where the drive(s) stand up, allowing you to use a small (~5 in) desk fan for cooling. They are sometimes on sale for around $20.
amazon[.]com/Inateck-Docking-Station-Offline-Function/dp/B06XYL599P/ref=sr_1_30?_encoding=UTF8&c=ts&dchild=1&keywords=Computer+Hard+Drive+Accessories&qid=1622759717&s=pc&sr=1-30&ts_id=11548952011
Smaller external conventional hard disks are often on sale -- 5TB versions are typically around $100 -- but they're slow [if that matters to you] and can be unreliable, e.g. I had a Seagate go bad within a month.
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With the necessities out of the way, Best Practices...
Depending on size & your upload speed, store anything you work on in the cloud. Win10 makes it easy to store docs etc. on OneDrive, you can choose whether you want to store them on your hard disk too, and you can easily add folders to backup, like those with your saved game details. This stuff continuously syncs, so you don't have to worry about backing up or copying anything multiple times a day.
Especially if you have several larger games or apps, consider putting most things Not Windows on another partition, on the same or another disk. You back up partitions -- when you choose to back up a complete disk, you just back up all of the partitions. Win10 gets updated once or twice a month, so you just need to back up that partition once or twice a month. Stuff like apps & games may get updated more rarely, or added to more frequently. It's Much more efficient to just back up what you need, When you need. Also consider how long it takes to add an app or game, and how long it takes to apply an update when one is available. I use a Razor mouse, and the software updates pretty frequently. OTOH updates don't take long at all. It doesn't make sense to spend 10-15 minutes backing up the Win10 partition every time the Razor software updates, when it only take 3-4 minutes to update the software -- if I had to restore the latest backup, I'd just have to spend another 3-4 minutes updating the Razor software. You can further customize your backup strategy based on your wants/needs, e.g. maybe a partition just for GOTD that you'd back up more frequently. If you want to be safest, store your backups in more than one place. Switching between two or more external drives -- one this month, the other next month -- **may** provide some added protection from ransomware etc.
TEST your strategy for restoring backups. Make sure that you know how to boot to the USB stick that Macrium Reflect lets you create. If you've got the disk space, it *may* be more convenient to just install a 2nd copy of Win10 just for backup & restore, and in case of emergencies. Using a smaller SSD in an external housing to make a Windows to go drive with Rufus works pretty well too.
Lastly, note that you can mix and match strategies too. You can have a Macrium Reflect bootable USB stick and a Windows to go drive for example -- you may prefer to use the drive but just in case you have the USB stick too. You can restore a backup stored on an internal disk much faster than when it's stored on a USB drive, but you have no protection if that drive fails, so you can perform a back up to an internal drive, then copy it to an external drive. Whatever works best for you -- as long as you back up of course. :)