Wifi via the Spectec MiniSD card

The Q9C says it supports WiFi, though you don't get that functionality right out-of-the-box. You can get an SDIO card that fits in the MiniSD slot to add the functionality, which is useful if you don't have a data plan and want to use the internet or if you are traveling internationally and won't have access to your data plan.

The only company I'm aware of currently selling a MiniSD WiFI card is Spectec, and they're surprisingly reasonably priced. The card most people are getting for this phone is the SDW-822 which supports 802.11b (the card that supports g costs nearly twice as much). There's a "regular" version of the 822 card for around $35, and a "Motorola" version with the same model number for around $45.
I tried to verify with Spectec what the differences were and was essentially told that the Motorola version was required since I had a Motorola phone running WM 6.0. However, the seller got mixed up and sent me the regular version of the card so I decided to try it anyways using the updated WM6.0 driver off their website. It turned out that card worked just fine, and I confirmed with Spectec that there isn't any risk of issues down the road if I got it working right now. Basically they said that the Motorola version was designed for a lower power requirement since older/other versions of the Q didn't supply enough power through the miniSD port.

So you can get the Spectec MiniSD Wifi card, and the regular version will work just fine in the Q9C. I do not know if it will work in other versions like the Motorola Q9M.

Sprite backup is excellent

I am not a big fan of apps that cost money because there's always more features I'd like to have and it would cost a boatload to pay for every app that improves the Windows Mobile experience. However, in the case of Sprite Backup I'm willing to make an exception.

Sprite Backup is a pretty simple app that lets you create a complete backup of your phone, with apps, contacts, registry settings, and literally everything on your phone getting backed up. The full version will even let you schedule backups and give some more options, but I found the lite version was all I needed since it lets me intiate backups from my computer that get stored on the computer as well as initiate a backup on my phone which can store the backup to a storage card for when you're not in reach of a computer.

It's extremely reassuring knowing that if I install an experimental (or even an established) application and it ends up killing my phone, I can restore it to exactly the configuration it has today. And if I lose my phone or even upgrade to a different Windows Mobile device, I can still recover the things I want again.

Move your Pocket Internet Explorer (PIE) Cache to SD

You can get Pocket Internet Explorer (PIE) to store your cache, cookies, and history to a storage card instead of to your phone. This is a really good thing because otherwise the cache can grow quite large and slow down the phone unless you clear it out regularly. In order to point PIE to an SD card there's just two steps, but one of them is a registry hack which can be risky if you've never done one before.

First, use File Explorer in ActiveSync or the File Manager on your phone and make 3 folders on your storage card like this:

\Storage Card\ietemp\cache
\Storage Card\ietemp\cookies
\Storage Card\ietemp\history

Also, make sure to clear your current cache, cookies, and history through PIE so you don't leave lingering files on your device.

Then, use a registry editor (you can find one called PHM for free) and go to
HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders

Edit these values:
Change the Value Data for Cache to \Storage Card\ietemp\cache
Change the Value Data for Cookies to \Storage Card\ietemp\cookies
Change the Value Data for History to \Storage Card\ietemp\history

After that, make sure to restart your phone, and you should be good to go.