Building a new character for a 1-20 campaign

[Name2020]

As the title says I am playing in a level 1-20 campaign my friend is running it with 3 other guys plus me so I decided to switch things up, I always play melee classes because those are the most fun for me but I want to try a spellcaster, my friend showed me the Hexblade and when I saw it I was in love. We currently have a half-elf rogue and a human barbarian, the last guy in the party wanted to play a cleric so I basically had the go ahead to play a warlock. I really want to play a sort of Han Solo or Lando type character, got the sleight of hand and card tricks, but also employing some magic to be extra persuasive. However I still want my warlock to get some oomph from my spells. Is there anyway to get this from a character.

[Galithar]

The most oomph is going to come from the fact that you have the ability to deal at will damage like a Martial class. Agonizing blast means you pretty much keep up with damage with anyone but an optimized fighter with GWM or Sharpshooter. Alternatively if you go Pact of the Blade you can melee pretty well. The biggest drawback is, despite what some people will say about medium armor and shield proficiency, you don't really have much in the way of defense to allow front line standing power.

I recommend going Pact of the Tome. It will allow you to pick up extra cantrips that can help with your flavor. Add things like minor illusion, guidance and prestidigitation. Then take the invocation for rituals to get a lot of good out of combat usefulness. Then run with a free hand, component pouch on your belt, and a shield. You can cast all your spells and fight with Eldritch Blast with 1 or more invocations to boost it.

Warlocks are very versatile if built right, and if you're getting 2+ short rests per long rest you will feel pretty powerful. If you frequently get less than 2 short rests you just have to adapt a little. Hex (from level 5 on) lasts 8 hours. If you can maintain concentration and attack with Eldritch Blast 2d10+2d6+6(or more depending on Charisma) is a decent amount of damage.

Now that said you probably were drawn to the Hexblade due to its melee capabilities since that's your preferred character type. Assuming you can get a 14+ Dex make good use of that medium Armor proficiency. I see you want to be Lando/Solo type character. So if you can manage to get a higher Dex (for your sleight of hand checks) then Armor of Shadows could be superior to medium armor, especially if there are multiple party members vying for any magical medium armor.

Edit: As for how to get the most from your spell slots, you want to look for spells with long durations and always try to find high level spells to cast versus using low level spells. Unlike most other casters you have little need to keep low level spells. Every chance you can forget a low level spell that doesn't scale, or scales poorly, for one that is more efficient for the slot. High level Armor of Agathys is one of the few level 1 Spells worth keeping in my opinion. At level 9 when you're casting with 5th level slots it's one of your few good choices for maintaining durability if you choose to enter melee. 25 temp HP and up to 625 damage (super exaggerated... You only get that much if you're hit 25 times for one damage) more realistically you'll probably get 25-75 points of damage per casting. The lower strength the enemy is the better this works obviously. It's also devastating against enemies that rely on a series of lower power multi-attacks for their damage or against weaker mobs.

[Bobthewizard]

Hexblade is such a great dip on sorcerers, paladins, and bards that some people miss out on how fun it can be as a single class. You need to decide if you want to blast or fight in melee.

For blasting, you'll take agonizing blast and eventually repelling blast and maybe lance of lethargy or grasp of Hadar. I'd go pact of the tomb or chain for this. Big, control spells work well for this - hold person, hypnotic pattern, fear, banishment.

For melee, you'll want improved pact weapon, thirsting blade, eldritch smite and life drinker. You'll definitely want to take pact of the blade. You could still take agonizing blast for a good fallback ranged attack. 2 levels of fighter or paladin can be great for this path if you want. The spells above are all still good but also look into hellish rebuke and armor of Agathys.

Otherwise, take flavorful invocations and spells. You won't be casting a spell every turn, but hopefully in most combats you could cast something. Look for spells that upcast well since your slots are always at the highest level, and be make sure to change your spells each time you level up. Anything that gets more targets is great to take once you have higher level spell slots - hold person, invisibility, fly, and banishment. Misty step and dimension door are good too but I'm always hesitant to use limited spell slots on single round movement.

Spells can be used to generate advantage - darkness/devil's sight, shadow of moil, eventually foresight. My favorite version of this is a half-elf with a greatsword taking elven accuracy to get triple advantage to make up for the -5/+10 of GWM. I think it's the only build that lets you combine those two. Starting at level 1 though I might forego eventual elven accuracy for the PAM feat on a variant human. Then hex with PAM gets 2 attacks at level 1 with an additional d6 on each attack. Depends how quickly I thought we'd level up.

Sorry for the rambling. So many choices.