IMHO, the simplest (if not necessarily most optimal) approach is this:
Code:
Character Plan by DDO Character Planner Version 03.11.02
DDO Character Planner Home Page
Level 20 True Neutral Elf Female
(1 Fighter \ 1 Rogue \ 18 Ranger)
Hit Points: 314
Spell Points: 355
BAB: 19\19\24\29\29
Fortitude: 16
Reflex: 20
Will: 5
Starting Feat/Enhancement
Abilities Base Stats Modified Stats
(32 Point) (Level 1) (Level 20)
Strength 16 23
Dexterity 17 24
Constitution 14 16
Intelligence 12 14
Wisdom 8 8
Charisma 8 8
Tomes Used
+2 Tome of Strength used at level 7
+2 Tome of Dexterity used at level 7
+2 Tome of Constitution used at level 7
+2 Tome of Intelligence used at level 7
Starting Feat/Enhancement
Base Skills Modified Skills
Skills (Level 1) (Level 20)
Balance 7 11
Bluff -1 -1
Concentration 2 3
Diplomacy -1 -1
Disable Device 5 25
Haggle 3 3
Heal -1 -1
Hide 3 7
Intimidate -1 -1
Jump 7 10
Listen -1 1
Move Silently 3 7
Open Lock 7 25
Perform n/a n/a
Repair 1 2
Search 5 27
Spot 3 24
Swim 3 6
Tumble 7 11
Use Magic Device 3 22
Level 1 (Rogue)
Skill: Balance (+4)
Skill: Disable Device (+4)
Skill: Haggle (+4)
Skill: Jump (+4)
Skill: Open Lock (+4)
Skill: Search (+4)
Skill: Spot (+4)
Skill: Tumble (+4)
Skill: Use Magic Device (+4)
Feat: (Selected) Point Blank Shot
Level 2 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+0.5)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Feat: (Favored Enemy) Favored Enemy: Undead
Level 3 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+0.5)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Feat: (Selected) Weapon Focus: Ranged Weapons
Level 4 (Ranger)
Ability Raise: STR
Skill: Disable Device (+1)
Skill: Open Lock (+0.5)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Level 5 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+0.5)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Level 6 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+0.5)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Feat: (Favored Enemy) Favored Enemy: Giant
Feat: (Selected) Mental Toughness
Level 7 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+0.5)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Level 8 (Ranger)
Ability Raise: STR
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Level 9 (Fighter)
Skill: Disable Device (+1)
Skill: Use Magic Device (+1)
Feat: (Selected) Improved Critical: Ranged Weapons
Feat: (Fighter Bonus) Improved Critical: Slashing Weapons
Level 10 (Ranger)
Skill: Disable Device (+1)
Skill: Search (+2)
Skill: Spot (+2)
Skill: Use Magic Device (+1)
Level 11 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Level 12 (Ranger)
Ability Raise: STR
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Feat: (Favored Enemy) Favored Enemy: Evil Outsider
Feat: (Selected) Toughness
Level 13 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Level 14 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Level 15 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Feat: (Selected) Power Attack
Level 16 (Ranger)
Ability Raise: STR
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Level 17 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Feat: (Favored Enemy) Favored Enemy: Construct
Level 18 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Feat: (Selected) Toughness (or other feat)
Level 19 (Ranger)
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Level 20 (Ranger)
Ability Raise: STR
Skill: Disable Device (+1)
Skill: Open Lock (+1)
Skill: Search (+1)
Skill: Spot (+1)
Skill: Use Magic Device (+1)
Enhancement: Rogue Haste Boost I
Enhancement: Ranger Sprint Boost I
Enhancement: Ranger Arcane Archer: Imbue Acid Arrows
Enhancement: Ranger Arcane Archer: Imbue Explosive Arrows
Enhancement: Ranger Arcane Archer: Imbue Force Arrows
Enhancement: Ranger Arcane Archer: Imbue Force Burst Arrows
Enhancement: Ranger Arcane Archer: Imbue Slaying Arrows
Enhancement: Ranger Arcane Archer: Imbue Terror Arrows
Enhancement: Elven Dexterity I
Enhancement: Elven Dexterity II
Enhancement: Valenar Elf Melee Attack I
Enhancement: Valenar Elf Melee Attack II
Enhancement: Valenar Elf Melee Damage I
Enhancement: Valenar Elf Melee Damage II
Enhancement: Elven Ranged Attack I
Enhancement: Elven Ranged Attack II
Enhancement: Elven Ranged Damage I
Enhancement: Elven Ranged Damage II
Enhancement: Racial Toughness I
Enhancement: Racial Toughness II
Enhancement: Ranger Favored Attack I
Enhancement: Ranger Favored Attack II
Enhancement: Ranger Favored Damage I
Enhancement: Ranger Favored Damage II
Enhancement: Ranger Favored Damage III
Enhancement: Ranger Favored Damage IV
Enhancement: Ranger Arcane Archer: Conjure +2 Arrows
Enhancement: Ranger Arcane Archer: Conjure +3 Arrows
Enhancement: Ranger Arcane Archer: Conjure +4 Arrows
Enhancement: Ranger Arcane Archer: Conjure +5 Arrows
Enhancement: Ranger Arcane Archer I
Enhancement: Rogue Sneak Attack Training I
Enhancement: Ranger Dexterity I
Enhancement: Ranger Dexterity II
Enhancement: Ranger Dexterity III
Enhancement: Fighter Toughness I
Enhancement: Rogue Improved Trap Sense I
But as an elf, you can do something more heavily-multiclassed and take the racial AA line instead. Have a look at my Triple A build for one example.