Savegame editing. You can find the traits section in the save, then replace the number of their education trait with the number of the trait you want. They’re listed as numbers, which you can get by examining the file My Documents\Paradox Interactive\Crusader Kings II\logs\setup.log and searching for the string Trait #1. You’ll get a series of lines like this:
[trait.cpp:849]: Trait #1 tag = amateurish_plotter name = Amateurish Plotter
Thus, replacing trait 1 with trait 4 in the savefile turns an amateurish plotter into an elusive shadow. If this is really too much work, the first twenty traits, in vanilla, are the education traits. They’re arranged in groups of four, from worst to best. Therefore, to give a character the best education, you can look for the trait with a number from 1 to 20, and increase it to the next multiple of 4.
If the character is a child, you can give him or her an education trait with the add_trait console command, and it will stick. You can also add a second education trait to yourself this way, but it won’t remove the previous one.
Or you can just read this thread, ive posted a full trait number list, and someone else posted the original's but for quickness sake here is the trait number list:
############
# EDUCATION
############
# INTRIGUE OUTCOMES
1 amateurish_plotter
2 flamboyant_schemer
3 intricate_webweaver
4 elusive_shadow
# DIPLOMACY OUTCOMES
5 naive_appeaser
6 underhanded_rogue
7 charismatic_negotiator
8 grey_eminence
# STEWARDSHIP OUTCOMES
9 indulgent_wastrel
10 thrifty_clerk
11 fortune_builder
12 midas_touched
# MARTIAL OUTCOMES
13 misguided_warrior
14 tough_soldier
15 skilled_tactician
16 brilliant_strategist
# ECCLESIASTICAL OUTCOMES
17 detached_priest
18 martial_cleric
19 scholarly_theologian
20 mastermind_theologian
########################
# HEALTH - Events
########################
21 stressed
22 depressed
23 lunatic
24 possessed
25 ill
26 pneumonic
27 syphilitic
28 leper
29 wounded
30 maimed
31 infirm
32 incapable
33 drunkard
34 has_tuberculosis
35 has_typhoid_fever
36 has_typhus
37 has_bubonic_plague
38 has_measles
39 has_small_pox
############################
# SOFT STATUS - Undecided
############################
40 crusader
############################
# HARD STATUS - DO NOT ADD OR REMOVE!
############################
41 bastard
42 twin
43 legit_bastard
44 pregnant
45 excommunicated
46 kinslayer
47 homosexual(adding didnt hurt me)
#####################
# POSSIBLY CONGENITAL
#####################
48 clubfooted
49 harelip
50 hunchback
51 lisp
52 stutter
53 fair
54 ugly
55 dwarf
56 genius
57 quick
58 slow
59 imbecile
60 inbred
61 strong
62 weak
################################################
# LIFESTYLE - Events - only 1 lifestyle (adult)
################################################
63 celibate
64 hedonist
65 scholar
66 gardener
67 mystic
68 impaler
69 duelist
70 hunter
71 poet
72 falconer
################################################## ###############
# PERSONALITY - Events, should happen more often during childhood
################################################## ###############
# THE SEVEN SINS AND VIRTUES
73 lustful
74 chaste
75 gluttonous
76 temperate
77 greedy
78 charitable
79 slothful
80 diligent
81 envious
82 kind
83 wroth
84 patient
85 proud
86 humble
# OTHER
87 deceitful
88 honest
89 craven
90 brave
91 shy
92 gregarious
93 ambitious
94 content
95 arbitrary
96 just
97 cynical
98 zealous
99 paranoid
100 trusting
101 cruel
################################################## ###############
# Leadership Traits
################################################## ###############
102 light_foot_leader
103 heavy_infantry_leader
104 cavalry_leader
105 inspiring_leader
106 trickster
107 organizer
108 defensive_leader
109 experimenter
110 flanker
111 aggressive_leader
############################
# HARD STATUS?
############################
112- mujahid(adding to a muslim didnt hurt me)
############################
# Muslim Traits
############################
113 hajjaj
114 on_hajj
115 faqih
116 hafiz
117 sayyid
############################
#Christian Pilgrimage
############################
118 pilgrim
############################
# Other Muslim
############################
119 mirza
############################
# Other
############################
120 scarred
###### ############ ######
# NEW # # Untested-LoR # # NEW #
###### ############ ######
121 eunuch
122 blinded
#########################################################################
# Hard coded to be given correctly and affect inheritance laws in the ERE
#########################################################################
123 born_in_the_purple
124 augustus
#######################
# New Leadership Traits
#######################
125 flat_terrain_leader
126 rough_terrain_leader
127 mountain_terrain_leader
128 desert_terrain_leader
129 holy_warrior
130 unyielding_leader
#######################
# Untested SI #
#######################
131 has_aztec_disease