I started getting serious about learning how to mod and solder on my own about a month or so ago. I wanted to work up to tackling my own UniBIOS install on my AES, so I began with a few less expensive and easier console mods:

Sega Genesis model 1 rear stereo RCA jacks.
Sega Genesis VA2 & VA3 jail bar fix.
Upgraded palette toggle switch for the NESRGB.

Then I moved up to a little more difficult mods:

Sega Genesis VA3 audio filter cap upgrade (gives it the same fidelity as the VA2).
NESRGB JTAG port on my NES front-loader (with help from Ste Kulov on the adapter board).
SNES 1CHIP-03 proper csync restoration (SMD kit).
SNES 1CHIP-03 digital audio TOSLINK mod.
SNES junior RGB + S-Video bypass board install.

After doing all that and collecting a nice set of various tools for modding, I decided it was time to knock out that UnibIOS install. I'm happy to report it went quite smoothly and everything has been working perfect!

Below are pics I took after each step of the process. I wasn't totally satisfied with my solder work, but I felt it was nothing to get too upset about for a first attempt: