By definition everything in a LLC is muddled in with your personal finances. That's why it's a "pass-thru entity". For tax purposes, they really are one and the same.
It goes like this:
LLC files form 1065
Form 1065 includes income / expenses of the LLC
Attached to form 1065 is a form K1 for each member
Form K1 includes the (net profit/loss * member's % ownership) + guaranteed payments (like a salary)
You file form 1040
Attached to form 1040 is your copy of the K1, which gets treated as additional income
You may also attach your personal business expenses [1]
You pay taxes on this ammount
So you see, LLCs file tax forms completely separately, it's only the check you have to write to the government that's "pass-through".
[1] Your personal business expenses are expenses that came out of your personal account for a business expense, so like a reimbursable expense. This gets reported on your personal taxes rather than the company's separate business expenses that came out of the company account. In general, just try not to do this if you can help it, as it just makes things more confusing.
For a small business with one owner, a Schedule C (or C-EZ) attached to the 1040 will suffice. No need to send a 1065 to the IRS and then submit a K1; it is just a small business in the eyes of the IRS.
Keep it simple by keeping track/records of your business income and expenses and report it on the Sched C which attaches to your 1040.
Note: I am currently taking a corporate tax course & studying for the CPA exam. I prepared taxes as a VITA volunteer last year.
With a single-person LLC, it's even simpler, because there is no (2). This is why single-person LLCs can file a Schedule C as a simple attachment to their own taxes, which gets reported on personal taxes as other income, just like the K1 would. And Schedule C is still reporting all of the company's income / expenses separately than the individual's other financials, so there is still no "muddying up" between business and personal finances.