Follow the content you like from popular users you know. Then add the relays they use. Between 10 and 30 seems fine.

Look at replies occasionally and jump into conversations to make new connections.

Figure out what kind of experience you want then connect with users offering that. Do you want to get a good laugh or do you want to argue or do you want deep philosophical conversations or do you want to learn about farming? Trending hashtags and mutual friends can help you find that experience.

Each client provides something different. Some might like damus while others might like primal. I personally use both for different reasons. I like primal because it lets me keep up with my feed but does give me fomo sometimes. I like damus because it is so smooth and gives me the most accurate notification feed. Experiment with 2-3 clients and see what you like.