As early as I could, I chose special abilities (perks) that provided bonus experience, up to a max of 30% extra. I also made sure to get my beauty sleep. Being well-rested provided another 10% boost, but because it was added after the perk bonuses, it worked out to 13% of the base value, so every 100 points earned netted me 143. Better still, it always rounded up. Walter, a mechanic in the town of Megaton, became my best friend in the world because he couldn't get enough scrap metal. I didn't need the cash (all the ammo I found became currency), but each piece garnered five points of precious experience. With perks, sleep, and favorable rounding, I haggled that up to eight points apiece -a 60% increase! If this doesn't seem that significant to you, you need to consider just how much scrap metal is lying around the capital wasteland.
I couldn't be satisfied with being just stealthy enough to earn critical hits, I needed to play this as a stealth game proper.
The perks that came with each level also allowed me to specialize in non-lethality. I took a robotics perk that let me disable a mechanical enemy if I could sneak up on it. I became an Animal Friend, which caused mole rats, wild dogs, and, most importantly, mutated bears to see me as "ally" instead of "meat." This didn't just reduce the amount of hostiles I encountered; it also saved my skin. In just one example: Out in the wasteland, with limited cover, I ran afoul of a super mutant grunt with an assault rifle. It was broad daylight, and he would have had a bead on me for quite some distance if I had to run. But before I needed to start up a steady stream of pain meds, a powerful Yao Guai mutant bear leapt from a nearby cliff. With one claw swipe, the grunt's assault rifle went flying. With the next, his arm came off. Through savage violence I was saved, but my hands stayed pristine, blood-free.
Scenes like that, all the more memorable because of their unscripted nature, made me appreciate the value that this play style brought to the game. Sure, in a normal playthrough you can stumble upon a bear mauling a super mutant, or witness a deathclaw obliterating a Protectron bot with one slash, but it means so much more if the Yao Guai is your ursine guardian angel, or if you activated the clunky Protectron strictly to serve as a diversion (and useful scrap metal!).
The apex of this no-killing experiment came around the middle. Quests were frequently sending me into heavily-infested areas, and the option to lie about completing them was becoming a rarity. Getting out alive required some serious sneaking chops. In a normal playthrough, stealth in Fallout 3 is primarily to facilitate killing -bonus damage to enemies caught unaware- and if sneaking fails, no worries, just start shooting. For me, getting spotted was much more problematic.
But, dammit, the troops stranded on the roof of this hotel weren't going to rescue themselves, so if this quest was to be completed I had to get up there. I couldn't be satisfied with being just stealthy enough to earn critical hits, I needed to play this as a stealth game proper. This meant watching enemy patrols, being aware of lines of sight at all times, and enduring some nail-biting moments when I had to leave a "safe" spot without knowing where the next one was.