I try to go as long as possible between Long Rests. So I take advantage of items that give free spells, items and abilities that restore spell slots, and class abilities that refresh on Short Rest.
My current party makeup is My Warlock, Shadowheart, Gale, and Halsin. Though I also used Battlemaster Lae'zel before trying Halsin.
Shadowheart I've made super Healer focused with great AC. She has a necklace that gives a free Healing Word and Mass Healing Word, and different armor pieces with bonuses when Healing like a free 2 HP to the person she heals, she get healed for 2 HP when Healing someone else, and free 3 temp HP to the person she heals. It's made Healing super effective.
I gave Gale an item that gives a free Magic Missile and when combined with another item that adds an extra Missile to the spell when cast, it's great at finishing off enemies that annoyingly survived with low health without wasting a spell slot. He also has an item that gives a free Scorching Ray. Plus, Wizards have Arcane Recovery which comes in handy.
Halsin I like to use as a Wildshape tank if he needs to, and Wildshape refreshes on Short Rest for Moon Druid, so it's easy to stretch his spells. When he has to cast spells, I pumped his Spell Save DC through items and ASIs to make them effective.
Lae'zel I also use as a tank. She has decent AC with the Mithril Splint, she's using a bunch of Githyanki specific gear that give bonuses if a Gith is wearing them, and Battlemaster's are just strong with the right Manuevers, and they refresh on short rest. She also gets Githyanki specific racial spells like Misty Step. Unfortunately, she ended up with all three debuffs from the Zaithisk, so to make up for the slightly lower HP and to make her relevant when compared to Karlach, I gave her a Periapt of Wound Closure, which makes all incoming Healing automatically maxed out, like Beacon of Hope. So Shadowheart's Healing is even better, Second Wind is great, and I believe Short Rest Healing also gets maxed but don't quote me.
For my Warlock MC, he's a Pact of the Blade Zariel Tiefling. He's using the Blood of Lathander as his Pact Weapon, gets free Smites from his race, and I took Durable to make every Short Rest a full heal. I use big AoE crowd control like Hunger of Hadar when needed, Counterspell in the back pocket, Eldritch Blast for range, and close in for melee. Plus Warlock spell slots refresh on Short Rest.
To top it all off, I use the Pearl of Power Amulet thing that restores up to 3 levels of spell slots. It's free to use and recharges on Long Rest, but I keep it in my inventory at all times and usually swap it between Shadowheart and Gale to help stretch spell slots further. I also just recently acquired a similar amulet that restores a single spell slot of any level 1-6, so that'll stay in the inventory as well.
We get two Short Rests a day, so I can go a pretty long while before needing a Long Rest.
