People care more about what they helped build, including relationships, so invite contribution instead of doing it all yourself.
The idea
Researchers Norton, Mochon and Ariely found that people value IKEA furniture they assembled themselves more than it's actually worth, and value their own amateur creations about as highly as expert ones. That's the IKEA effect, and it applies to relationships too: the more effort someone puts into you, the more they care about you. So while it's natural to fear imposing, a request that takes some effort can be good for the relationship. Just make sure the effort is worth it.
How to do it
Stop trying to do everything solo. Ask for help.
Turn an invitation into participation: a dinner you co-host, or a meal the guests cook together.
Any joint activity works: volunteering, painting, hiking, team sports.
If you're asking for effort, make sure it's worth it.
Example
Jon Levy built The Influencers, an invite-only community of more than 1,500 tastemakers (musicians, actors, even Nobel laureates), by having groups of 12 strangers cook a dinner together. Making a meal with people you've just met lets the IKEA and Ben Franklin effects kick in, and everyone bonds more quickly. He started with friends and asked each group for recommendations afterward.
The Ben Franklin Effect: People who've done you a favor tend to like you more and do more, so start with small, interesting, easy favors.
Side by Side: Trust grows fastest through shared experience, so add an activity, like a walk, a game or a hot sauce challenge, to plain conversation.
Manufacture Shared Experiences: A slightly intense shared experience bonds people faster than polite chat, and even an event that goes wrong becomes a story you share.
Asking for Help Is a Gift: Helping lights up the brain's reward centers, so never asking for help denies the people who care about you a genuine feel-good moment.