This  post originally appeared on First Round Review.

Last fall, we overheard that Twitter Engineering Director David Loftesness had some solid wisdom about training newly-minted engineering managers -- an often precarious transition. So we sat down with him to see what tips he had to offer, and we were blown away. Not only did David have actionable insights to share, he had plotted out a concrete 90-day plan for engineers making the leap to leadership. We couldn't have been more excited to publish the piece -- it's so representative of First Round Review's mission to bring original, non-obvious advice to light.

The response was inspiring. Not only did it hit No. 1 on Hacker News, it was read far and wide by thousands. Clearly something had struck a chord. We watched as it got passed around the largest engineering teams in San Francisco. We eagerly invited David to host a dinner for rookie engineering managers in our community, which was a smash success. And now we're awaiting his forthcoming book. It's amazing what sharing this type of knowledge can do. We've seen it make magic happen for the people who provide it and the people who read it.

The Review is now over two years old and home to dozens of stories that have resonated and made a difference like David's. In 2015 alone, we added nearly 100 new articles, full of granular how-to's for designers, product managers, marketers, recruiters, sales leaders, executives and many more. What follows is a list of the 30 most impactful, change-making pieces of advice drawn from everything we published last year.

But as we look back and ahead, what's truly exciting is how much we've learned about what our audience actually wants and needs, and how we can do our part to make the entire tech ecosystem stronger. This is what will drive us to talk to even more remarkable people, try new things, and tell great stories in 2016. Join us. Won't you?

Kim Scott has built her career around creating bullshit-free zones where people love their work and working together. Now an acclaimed coach for Twitter, Shyp, and Qualtrics among others, she's made one simple tool the cornerstone of her teaching: Radical Candor. Basically, bosses need to tell their employees when they're screwing up, but it very rarely happens. Scott proposes a framework to make this easier:

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If the vertical axis is caring personally and the horizontal axis is challenging directly, you want your feedback to fall in the upper right-hand quadrant. That's where Radical Candor lives. It's the combination of caring a great deal and being willing to deliver difficult feedback, Scott said. "Radical candor is humble, it's helpful, it's immediate, it's in person -- in private if it's criticism and in public if it's praise -- and it doesn't personalize."

"I would argue that criticizing your employees when they screw up is not just your job, it's actually your moral obligation."

Slack may go down in history for having the best go-to-market experience ever. Out of the gate it was crowned a unicorn and universally loved by its users. How did CEO Stewart Butterfield and his team accomplish this? For starters, they kept the product in beta for months to intimately understand their users, collect data and use it to fuel development. "We're fastidious about tagging all incoming messages across channels, collating, entering and retaining the data people share or send to us," said Butterfield. This has allowed them to play to customers' priorities, optimizing the features they cared about most (i.e. search, synchronization and simple file sharing). On the quantitative side, it also gave the company a benchmark for success. They saw that once a team exchanged 2,000 messages on Slack, they'd be hooked. The company took the hint and baked new mechanics into the user experience to get customers to that golden 2,000 message mark. Spoiler alert: It worked.

"The best metaphor I have for scaling a company is building one of those huge, complex towers out of Legos," says Molly Graham, COO of Quip and former Facebook culture architect. Early on at a startup, everyone's excited and has so much to do. But when you start to grow, a funny thing happens: People get nervous. "As new roles get added, you go through this roller coaster of, 'Wait, is that new person taking my job? What if they don't do it the right way? What do I do now?'" The emotions you feel when new people are coming in and taking over pieces of your job -- it's not that different from how a kid feels when they have to share their Legos. At a scaling company, giving away responsibility -- giving away that Lego tower you started building -- is the only way to move on to building bigger and better things.

"All else being equal, the fastest company in any market will win," says Dave Girouard, CEO of Upstart, and former head of Google Enterprise Apps. "Speed is a defining characteristic -- if not the defining characteristic -- of the leader in virtually every industry you look at," he said.

"I believe that speed, like exercise and eating healthy, can be habitual."

The key takeaway: WHEN a decision is made is much more important than WHAT decision is made. You need to consistently begin every decision-making process by considering how much time and effort that choice is worth. There are decisions that deserve days of debate and analysis, but the vast majority aren't worth more than 10 minutes. And, as you're executing, always ask this question: "Why can't this be done sooner?" Asking it methodically, reliably and habitually can have a profound impact on the speed of your organization. As Girouard put it: "A good plan violently executed now is better than a perfect plan next week."

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Last year, First Round Partner Josh Kopelman observed this about raising Series A funding: The number of seed-funded companies recently quadrupled, and most of them set out to raise larger than average A rounds. This has unintentionally exacerbated a Series A Crunch -- a rude awakening for companies that thought it would be easy to secure more capital. Kopelman's contention: This should fundamentally change the way early-stage founders think about raising money. For instance, some of the smartest founders he's worked with have raised larger seed rounds, buying themselves time to get more done before they pitch again. He also recommends forgoing party rounds to work only with investors who will roll up their sleeves to open doors, make intros, and concretely help with your next round. Then, once the money's in the bank, keep your burn rate low until you have product-market fit. "That's your best chance at building a big company that matters," Kopelman said.