Basic Warlock build:
Warlock 15 (15d6 HD)
BAB +11; base fort +5; bef +5; bwill +9
Eldritch Blast 7d6 (base range 60 ft; crystalkeep erroneously says 30 ft)
9 Invocations (3 least, lesser, and greater, each)
DR 4/cold iron
Energy Resist 5 (pick 2 energy types)
Fiendish Resilience 2 (free action 1/day fast healing 2 for 2 min.)
Detect Magic (Sp; at will)
Deceive Item (take 10 on UMD)
Imbue Item (UMD DC 15/25 +spell level to count as having an arcane/divine spell for item creation)
Invocations (standard action; generally 24 hr duration for non-attack invocations):
Least:
Eldritch Spear (blast shape): EB range extended to 250 ft; spell level 2
See the Unseen: 60 ft darkvision and
See Invisibility; spell level 2
Voice of Madness: 60 ft; SR; Will DC 12+cha negates;
confusion on one target for 8 rounds; spell level 2
Other options: Baleful Utterance (like
shatter, too complex to quickly describe

)
Lesser:
Eldritch Chain (Blast Shape): Until you miss, may jump the EB to up to 3 secondary targets beyond the first (no creature more than once); 2nd-ary targets take 1/2 damage; spell level 4
Fell Flight: Gain Fly speed = to land speed w/ Good maneuverability; spell level 3
Charm: 60 ft; SR; Will DC 14+cha negates;
Charm Monster on any living creature; permanent until new creature is charmed; spell level 4
Other options: Walk Unseen (
invisibility), Flee the Scene (
dimension door)
Greater:
Vitriolic Blast (Eld. Essence): EB does acid damage, ignores SR; target continues taking 2d6 acid each round for 3 rounds; spell level 6
Chilling Tentacles: 250 ft; no SR; 15 rounds of
Black Tentacles; grapple +23; 1d6 +4 damage; 2d6 cold damage per round to all in area (even if not grappled); spell level 5
Tenacious Plague: 1000 ft; 1 round cast time; 15 min; no save/SR; summon 5 contiguous, immobile locust swarms with +cha to distraction DC and attacks counting as magic weapons; spell level 6
Other options: Eldritch Cone (30 ft cone of EB; ref half), Devour Magic (touch range
greater dispel magic; gain temp hp)
Note, you can only add 1 eld. essence and 1 blast shape to each EB, so make sure you have at least 1 of each, but not too many. I just find Eld. Spear ever-useful as a backup.
Feats:
1: Point Blank Shot
3: Precise Shot
6: Empower SLA (EB)
9: Flyby Attack (note, can use a standard action between moves)
12: Quicken SLA (EB)
15: Improved Precise Shot? (need dex 19, but lets you fire into your chilling tentacles unerringly)
Other / human bonus feat / flaws: Fey heritage line if you can get the book; Ability Focus (EB; as I have it set up, none of your EB's allow saves anyway); Extra Invocation (must be a lower grade than the highest you could use at that level); Arcane Mastery (can take 10 on SR checks; useful if not taking Vitriolic Blast).