Is it a front or rear? Front can be done ok in a fork. Rear's a bit less so.
New nipples, don't reuse. Asides from building with old nipples being a shit experience, they fatigue. Nipple washers are one of the ways god shows us that he loves us.
The cheap Park gauge is useful - use it as instructed, not ignoring the numbers above. At tension 1/8th of of a turn can make a large difference in tension and you may not feel it. Uneven tension kills wheels far moreso than anything else. A dishing tool is also highly recommended.
Last tip - once you've built the wheel and it's as you want it, fit the tubeless tyre and then readjust tension. Wheels lose a fair bit of tension when a tubeless tyre is installed and I seem plenty of home built and even workshop built wheels lose tension rapidly on the first ride if this isn't done. I'm not a fan of prolock, but tend to soak all my batches of nipples in T9 until it evaporates off to wax.
Leonard Zinn's books have really good wheel building instructions - it's a great resource.
One tip I appreciate from my novice days is that when it starts to go wrong or get weird and you can't work it out, back everything off a quarter or half turn and start fresh. It's very easy to persevere and continually put more tension in to the wheel trying to chase something and next thing you'll be rounding off nipples or cracking the rim.