When I first started getting savvy about this game, I realized that a lot of things are much easier if I use my keyboard. I created what I call Find and Use.

By default, your
Delete key finds the ITEM nearest you,
F10 key selects the NPC nearest you,
Backspace key selects the MOB (enemy) nearest you (even the ones behind you).
U key is “use” – you can use anything you can select but some things don’t do anything.

Tab key selects the mob closest to you and each time you use it, it selects the next closest mob.

Similarly, I set up keys to select the
NEXT item (G for “get” for me) and
NEXT NPC (Y for me).

Now I can run with my left hand and search for items or NPCs (and use them) with my right hand.

Keyboard image in the WIKI.