They can only make assertions without evidence. I do not know about the origins of the universe but I will be honest about that. They do not know the origins of the universe they just claim to know what they do not know.

I do not believe there is a God, this has nothing to do with explaining the origins of the universe. I am in no way obligated to know the origins of the universe. I simply do not claim to know what I can not know.

They often assert we think something came from nothing, I assert I don't know, nor does it matter. Just because neither of us knows the origin of the universe does not mean we can assert that a being we can't prove exist, Does exist and created it.
The central problem with any philosophical argument is the only reason they resort to such mental gymnastics is they have no actual proof for God. I like to address that and avoid apologetics, none of them are good and they distract from the fact they can not prove their God exist.

To give you advice it is necessary to know:
In what context is the discussion occuring?
And with whom?

It's a failure of imagination. Creationists, even the ones who are scientists, must lack the imagination to conceive of the absolutely huge numbers which cause evolution. Billions of years, Trillions of generations. For an ape that has trouble with imagining groups larger than 1000 people these numbers are mind boggling. But they're real. (NB humans are the ape mentioned)

No design should be inferred from what we know of life. Humans saying their planet was made for them is the equivalent of a puddle believing a pothole was made for it. We grew to our environment and still we are very fragile away from our technology. Most of the universe is unsurvivable for humans. Further 97% of our DNA is agreed to be giberish. Only 3% of our genes do anything. That's like a cat walking on a keyboard and a word coming out of a paragraph of attempts.

Theology is like the tax cut bill. The real question is who does it serve? If one examines who benefits the most from believing in Santa Claus, it isn't the kids. The kids get some crappy toys, eventually find out it was a lie, and then get stuck stressing out over making everybody happy that one day a year when they grow up. Who benefits? IMO theology has nothing to do with mystical beings handing down instructions from on high. Instead all theology is a well considered social engineering scheme designed by those holding power and authority focused on maintaining that authority and reaping the rewards through imposing conditioned response learned from childhood on.

when we see a man made object, we know it's man made, because we've seen men make things, we know men (humans) exist, and we've seen the things they make. In other words, we have evidence. When we see "creation" which is a word made up by creationists, we know it's a natural occurance, because we've never seen anyone, or anything make a tree, or flower. To say it was made by a "creator", you would first have to show that this creator exists. Not the other way around.

I tend to find ways to use their own arguments against them. I've also been known to tell people of faith that, if their faith couldn't make room for science to be how people explained the work of god, then their faith wasn't very strong to begin with.

That usually shuts them right up,

Here's the thing about the word "design"... they are using it really weird. For being one with an engineering background, I was really annoyed to realize that they scarcely seem to give a definition of the what "designed by God" is or should look like. In other words, they don't seem to provide any pointers on how to tell the deference between such design versus fundamentally stochastic processes or even human-design processes. As such their claim to "design" is left in a very ambiguous state.

What you start realizing—when you look into the arguments for God—is that the words "design," "random," "nothing," "knowledge," "present," and "power" are all defined in archaic, meta-physical ways that, at this point in time, are so thoroughly detached from what those words mean in any sort of applied science as to be suspiciously useless anywhere else but those Theological/Religious arguments. They are used in intuitively interesting ways, but not ones that are compelling in practice.

Be very skeptical when you hear someone use any of those words.

This is why I simply don't much care about the teleological argument. Show me what non-design is first, then show me design that's NOT divine/supernatural, finally show something that is clearly designed, but NOT by either of the other two possibilities. I haven't seen anything like a clear case for this, and as such I am highly suspicious of their use of the word "design."

Design in nature is equally possible on its face as an innate feature as it could be caused by an outside intelligence. No need. Ockham’s Razor.

My usual response is "You are talking nonsense". I don't know how we came to exist and I don't care.

How does your god affect my day to day life?

Really? Prove it.