Auctions are difficult to give a whole lot of advice for, because each league can be wildly different from one another. Even in my league, which is over 10 years old now, every year seems to be different. In the past, the elite tier went for big, big money and then things settled in. This year, the elite tier were a few dollars less than in years past, but the middle tiers were elevated for a really long streak. Totally changed how I had to approach my draft once that became apparent.
So, with that said, my biggest piece of advice is to study the guys you like in each tier. I typically try to get someone in the middle of the tier so I can save a bit of money. I avoid the top dogs in the first tier because I don't like being hampered too much once the price points settle in a bit. If you get David Johnson, more than likely, you are going to spend almost half of your budget. He's great, but I just can't devote that much cash to one guy.
As others have said, wait on kicker and defense...or nominate a top defense for $2 fairly early in the draft. If someone wants to outspend you on that, great. If not, I'd be OK parting with an extra dollar to get an elite defense and not worry about carrying another one. There will be plenty of $1 receivers that you like at the end of the draft too.
This year, I like the middle tier of RBs and think you can pair two solid guys here (I got Demarco, Dalvin Cook, and Doug Martin for just a little more than the price of David Johnson). I love taking a top 5 wideout and then filling up later in the draft with high upside guys who will be cheap. Or take three of the second tier WRs.
In the end, I think the best advice is to not get (too) drunk and pay attention to how the draft is playing out. Don't feel like you need to bid on the first handful of nominations...but don't wait until the list of players you love at each position dwindles down to 2 or fewer players. You will overpay. Nominate players that you don't want (only nominate for $1...don't get cute), but others will want. And don't get too drunk. Did I say that already?