Gurps action 4 : Specialist is a great resource for that.
Take a basic mundane*, add a couple 25 cp skills set from Specialist, use the remaining 25 cp + quiks + disadvantages to customize (usually, including either a +1 to DX or IQ) and you have a credible 100 cp character ready to go.
*In my games, this would be the starting package for a young adult character in a mundane modern western world setting.
A player could remove items, but he would have to justify it.
Cost 25 cp
Code:
All stats at 10
**Languages
Native language (native/native)
**Advantages
Luck
One level in a 5 cp talent. (or 5 cp toward a 10 or 15 cp talent)
**Disadvantages
Pacifism (Reluctant Killer)
**Perks
Mundane background(current living area) [0]
Cultural familiarity(native culture) [0]
Dabbler perk (select 2 to 4 skills covering your studies or job training) [1]
Dabbler perk (select 2 to 4 skills covering your youth and background) [1]
**Skills
Area Knowledge (current background) [1] (if different from young)
Current affairs(select 1 between sports, politics, pop culture, local news, internationnal news) [1]
Housekeeping [1]
1 Cp in One of Carousing, Connoisseur (any), Games (any), Hobby Skill (any), Musical Instrument (any), Singing, or Sports (any) [1]
Computer Operation [1]
1 Cp in a Professional skill or job prerequisite skill [1]
1 Cp in Savoir-faire(job related) or streetwise or an influence skill [1]
1 Cp in swimming or hiking or driving or bicycling [1]