Sometimes, you’ll want a bit of an extra challenge in Terraria, and I know how you feel. So, to solve that problem I installed mods (mods are modifications to the game, for example altering the difficulty or changing gameplay)!
I go with the tModLoader to install the mods I use. All you do is install it with one of the links below, and then either select mod files to use, or use the pre-installed mod selector/download.
The installation of tModLoader is pretty simple to explain. All you do is download it, click extract, and extract them to your Terraria folder. You can find your folder at:
C:\Program Files (x86)\Steam\steamapps\common\Terraria
You can easily open that folder by holding down Windows+R, and then pasting the above in. Now just run the game! All done!