Straight off, I don't like the Eldritch Knight, I think it's a horrible subclass. I've seen some rumblings otherwise, so I wanted to see what other folks might be using or doing to enjoy the class.
RULE #1: NO MULTICLASSING
RULE #2: NO ASSUMPTION OF MAGIC ITEMS
This is about the subclass itself, without having to augment it with another class or through magic items. I'd like to see people's level-by-level build for their "best" or most enjoyable way to build the class. I'm mostly approaching this from the DM's side of things, just to see if I'm misunderstanding the subclass. Doesn't have to be built all the way to 20th, I'm really just interested in how it plays up to 8th level, maybe 12th level at most. Any good tricks/combos/insights that help understand it better I'd really appreciate.
I love the Eldritch Knight. It is my favorite fighter class. Here is how I would build it of I was making a character for a combat focused game. If it was not combat focused and was more balanced, I would start with 13 Wisdom and 12 Constitution but otherwise the same.
Female Drow
S16 D8 C14 I8 W10 CH17 (on point buy)
Trade weapon proficiencies for tools
Level-by-level:
1. Fighting Style - Superior Technique - Menacing Attack
3. Eldritch Knight - Shield, Protection from Evil and Good, Silvery Barbs, Booming Blade, Blade Ward
4. Drow High Magic Feat, Absorb Elements
6. Magic Initiate - Warlock (Green Flame Blade, Eldritch Blast, Armor of Agathys)
7. Arcane Lock
8. Shadowblade, Fey Touched Feat (Charisma - Hex and Misty Step)
10. Alarm, Friends or Prestidigitation or Message or Minor Illusion
11. Gust of Wind
12. Shadow Touched Feat (Charisma - Cause Fear and Invisibility)
13. Counterspell, Lemund's Tiny Hut, Remove Gust of Wind
14. Fly, ASI +1 Wisdom (11) and +1 Charisma (20)
16. Resilient Feat (Wisdom), Gust of Wind
19. Fire Shield either Warcaster Feat or Mage Slayer Feat
20. Dimension Door
I love this build. It is my favorite single class fighter!
Your fighter spell selections are really limited, so for me the trick is to play a Drow, get Drow High Magic and get more spells on feats. Your offensive spells should be based on Charisma. This helps two ways first at 12th level I have 9 leveled spells I can cast for free once a day plus Detect Magic at will (and being able to do it at will is a lot better than as a ritual). Then I can use slots to cast those spells too, since they are known and the EK is a known spell caster and they are all on a charisma save DC.
My Wizard/fighter spells provide stuff that does not need Intelligence (Shield, PEG, Silvery Barbs, Absorb Elements) plus some ribbon spells.
levels 8-12 is where this really shines. War Magic is online and is not yet outclassed by extra attack. You have a good ranged attack with Eldritch Blast, which you can combine with a thrown weapon attack through Warmagic, your low level offensive spells are still potent.