How do I fix a too-dry cement board underlayment mortar for bathroom tiling?

[Aria_P]

I'm tackling my first major DIY home improvement project by retiling the bathroom floor, and while I've watched countless tutorials, I'm hitting a snag with getting the mortar consistency right for the cement board underlayment. My first attempt was too dry and crumbly, and I'm worried about compromising the integrity before I even lay the tile. For experienced DIYers, what are your best tips for mastering material mixes and avoiding common beginner pitfalls on tile projects? How did you develop the confidence to trust your prep work, and what tools did you find indispensable versus ones you could have skipped for a job of this scale?