I've used Ubuntu quite a bit and dabbled in Slackware, but Arch seems like the perfect bridge between them. What are some things that you think I (and everyone new to Arch) should know? Thanks for your input.

Clear your schedule for a few hours, brew a pot of coffee/tea (not beer; common Arch rookie mistake), and follow this guide step-by-step:

https://wiki.archlinux.org/index.php/Beginners%27_Guide

You'll be fine (or decide Arch is not for you, which is also OK).

Not sure I agree with your statement "Arch as a bridge to Slackware" maybe more accurate to say they are "both bridges over the same water."

Thanks for your reply. I probably could have phrased that better, but I meant that Arch seems to be the perfect midground between Ubuntu and Slackware (in terms of package management, mainly). I'm not going to be using Arch as a bridge to Slackware, I'll probably be sticking with Arch for a while if all goes well.

I understand, just joking with you a little.

A fun, quick read is The Arch Way:

https://wiki.archlinux.org/index.php/The_Arch_Way

The thing you should do when you want to become a successful Arch user is the same that you have to when you want to become a happy Slacker: Read the documentation.
Arch has an excellent Wiki (links already given by snowpine) with a vast amount of knowledge about a broad spectrum of topics. By the way, most of their documentation is applicable to Slackware also (of course except the package management parts), the Arch Wiki was often a good help for me.

Never update your system partially. Only full update.
And try not to update if you don't need to - this will eat your time.

When you update running 'pacman -Syu', make sure you read the update logs fully.
When there is a *.conf.pacnew file for a package, make sure you explore the file to see what important changes are made.

AUR (Arch User Repo)

Unterstand the fine art of Zen meditation, always think positive, experiment with a PC you can miss until you're fluent enough, learn the patience of the Universe, be brave enough to "let it be" for a day or two and beyond all...learn to type...because Arch exists in the console, the rest is make-up

On a more practical note, things you could find handy:
- understand partitioning
- understand the use of /etc/rc.conf
- become fluent with nano
- have a PC handy to browse the online stuff
- get to know pacman, that's your friend
- go step by step, until you understand this, it's not hard, but it's a lot...
- bookmark all the documentation as much as possible.
- know en enroll in a good forum (wait, you're here already, okay, scratch that one )

Welcome to Arch