Warlock as skill-monkey?

[Golux]

So, our group doesn't have a Rogue, or a Bard. We have a Ranger, a Fighter; we used to have a Cleric, but he dropped out. And we have me, a GOO Warlock. We may be having a new fourth member to replace the Cleric, but I'm not too sanguine it'll be one of the classical skill-monkey classes.

Fortunately I somewhat saw this coming and put 16 in Dex and chose Criminal background, so I know my way around Thieves' Tools. I also picked Pact of the Tome so I can cast Guidance on myself. Any advice on what I should do further to this? My groupmates are NOT optimization-minded and I'm afraid we may be at a disadvantage. Thanks in advance.

[Kane0]

Prodigy or skilled feat are options, plus the Beguiling Influence invocation.
Downtime can also be used to learn tools.

[Eragon123]

Well you can use beguiling influence to pick up proficiency in persuasion skills, if you don't have them already.

Unfortunately, there are other skills.

What patron did you comport with?
If Archfey you have a 1/SR charm, if you are willing to go scary gandalf/galadriel on people. (though seriously that should be cha mod/SR)

Once you get access to 5th level spells you can ask the DM if you can grab skill empowerment.... but that's not guarenteed nor especially viable.

Multiclassing is an option but I don't like multiclassing so Ill let other people recommend bard or rogue.

Other than picking up the Skilled feat maybe? Or Prodigy?

[Kane0]

Oh theres also the invisibility invocation, which may or may not be useful to you.

[Blood of Gaea]

Be a Half-Elf and take the invocation for persuasion + deception. Remember that if you already have those proficiencies they can be put anywhere.

You might also consider 2-3 levels of Bard.

[Xihirli]

Pact of the Tome Book of Ancient Secrets will give you a lot of utility.

[Greywander]

A dedicated skill monkey isn't as necessary as it was in previous editions. Every character has at least four skill proficiencies, sometimes more depending on race, class, and feat selection, and everyone speaks at least Common and one other language, with either two more languages or two tool proficiencies (or one of each) from their background. Between 4 characters, you have at least 16 skill proficiencies, 4 non-Common languages, and 8 additional tools/languages. As long as you diversify, that gets you excellent coverage of skills, languages, and tools. And with Bounded Accuracy, you can still get by without proficiency in a skill you need, as long as someone has a decent ability score for that skill.

My biggest concern with the group you listed is that everyone is going to dump INT, unless the fighter was planning on going EK. As noted above with Bounded Accuracy, you don't need both proficiency and a high ability score in order to get by, although it's definitely preferable, so if everyone dumps INT then you should still be alright as long as someone has proficiency with INT skills.

Have you already started playing, or are you still in character creation? What exactly is the skill and ability score spread with your party? Is everyone dumping the same ability score and not taking proficiency in any of those skills?