My favorite Factotum build so far is the Factotum Archer, but that doesnt really come into play until about 9th level when you get Manyshot.
That being said, since all 3.5 1st party books are allowed, does that also mean flaws?
I suggest putting at least one point into the other knowledges that can be used with Knowledge Devotion, and taking that as your third level feat.
Arcana
Dungeoneering
Local
Nature
Religion
The Planes
Knowledge Nobility, I would only put one rank in, at MOST 5 for the synergy bonus to Diplomacy, and only if you are really wanting to be the party face/social person.
If you are going for a melee character, and you are going to be wearing light or no armor, put ranks in Tumble.
As for feats, personally I prefer to go the Manyshot path : Rapid shot, Point Blank Shot, Precise Shot, Manyshot
For a Human, this gives a feat progression like:
H: Rapid Shot
1: Point Blank shot
3: Knowledge Devotion
6: Precise Shot
9: Manyshot
If you can get a flaw, switch Rapid shot to a Flaw feat, so if you polymorph or whatever to another race, you don't the benefits of Manyshot.
If you decide to go this route, switch your Charisma and Dexterity.
Use Magic Device is a must. Even though a Factotum can cast spells, they technically have no spell list, making them unable to use most Spell Trigger and Spell Completion items without a UMD check.