If you want the TL;DR, follow the 5-by-5 rule:
Spread your stake across 5 good validators that all have less than 5% of the total stake.
First, visit the validator list on the Radix explorer to look at the validator nodes with less than 5% of total stake. Follow the links to the node-runners’ info pages, and pick 5 good validators that are performing well, seem trustworthy, and ideally with their nodes in different data centers.
How to wisely distribute your stake
Staking to validator nodes is a type of voting that the XRD token-holding community performs. Staking directly selects which validator nodes are allowed to participate in network consensus. So it is extremely important for each XRD holder to make an informed choice about staking validator nodes – like voting for a set of government representatives!
Radix provides a validator list in the Radix Explorer, where you can view the validator list and see information about each validator.
Here are some guidelines for choosing validator nodes to stake to:
Stake widely to many validators. Selfishly, you wouldn’t want to put all your eggs in one basket, and have one validator fall out of favor and you lose your incentive rewards. Even the most well-intentioned node-runner may be disconnected for reasons beyond their control.
Stake across a range of geographies. Diversity is important! A good, reliable, secure network should be made of node-runners with different types of deployments, in different locations – each with enough stake delegated to them to participate strongly in the network. Known community members are great, but so are professional node-running services, individuals who are making a strong effort to engage with the community, and others.
Stake to quality. Nodes you stake to should be trusted not only not to be an attacker but also to have the technical ability and commitment to operate a reliable node. See if they are communicating with the community on Discord or the Radix Validators Subreddit. Ask them questions! Please review the Subreddit as well as the #node-runner channel on Discord.
Don't stake to the very top validators. You might tend to want to delegate to the most popular nodes with the most stake already. But if only a few validators have too much stake, even an accidental disconnection could slow the network or (in an extreme situation) cause the network to halt temporarily. It’s essential to delegate “down ballot” to those lower in the list of 100 to ensure network performance and reliability.
Good stake delegation choices are an important responsibility of the community. A great outcome of the community working together to make these choices would be 100 different entities running 100 different validator nodes, each trusted by the community, and each with a comparable amount of delegated stake. While reality will undoubtedly be somewhat different from this, as an ideal to strive toward this would minimize the possibility of attack and make the network as resilient as possible in the case of accidental validator node failures.