Have Sorcerer as your first class to benefit from it's saving throws, hexblade equipment comes with the subclass automatically, so no worries there.
You need to determine if your going hard Sorcerer or hard Warlock because splitting your levels in half between the two leaves you just barely out of reach of better abilities from both of the classes. I suggest either a 14/6 split either way or taking 2 levels in Warlock and dumping the rest of your levels into Sorcerer. The last option is probably best for short campaigns as it remains pretty stable. If it's just a one-shot a 3/3 split is fine.
While Eldritch Blast is tempting, don't pick it up. Eldritch Blast is better for those that invest in the Eldritch Invocations for it, while I imagine you want to get into melee and so your plan is to slash instead of blast. If you need a ranged damage Cantrip, I suggest Toll the Dead (best damage as long as it has less than maximum damage, and uses an unusual Save for damage) or Fire Bolt (one of the most reliable cantrips: 120ft range, 1d10 damage, and be used on objects). As for Melee cantrips, Booming Blade, Green-Flame Blade, Lightning Lure, and Sword Burst are common choices. Make sure you have Prestidigitation and Minor Illusion for support.
There are lots of nice Eldritch Invocations. Personally, outside of the melee ones, I suggest looking into Beguiling Influence (for more skills), Eldritch Sight (you can't ritual cast as this character, but this will give you the infinite ability to detect magic), and Mask of Many Faces (infinite ability to magically disguise yourself).
I want to build a Half Elf Hexblade Patron Warlock multiclassing into Divine Soul Sorcerer. Can anyone give me any tips
Here's the suggestions I have: