As mentioned in this article, there's a dynamic minimum of DOT that you need to have bonded in order to nominate validators and get rewards, which you can see on the Targets page of Polkadot-JS UI.

If you don't have that amount of DOT, your options for getting rewards while staking solo are limited. But with the introduction of Nomination Pools, things are about to change. Nomination Pools are live on Polkadot, and everyone can nominate and receive staking rewards with as little as 1 DOT!

What are my options?

If you have already bonded less than the minimum needed

If you have bonded less than the minimum required to nominate and get rewards, you can unbond your DOT and join a nomination pool. Here's how:

1. Follow this guide to unbond your tokens

2. Wait for 28 days for your DOT to unbond and then follow Step 3 in the guide above.

3. Now that your DOT is transferable, you can join a nomination pool

NOTE: There are future plans to create a "fast unbond" option for accounts that have never been exposed to a validator. However, this feature is not live yet as of this writing.

If you haven't bonded your DOT

In that case, things are even simpler. All you have to do is join a nomination pool and start receiving rewards!

That's it!