The answers below are helpful, but they miss 3 out of the 4 major sources for recruitment:
1) Inbound flow (people come to you)
2) Outbound search (linkedin, etc...)
3) Referrals
4) External Recruiting

I would think about how your firm stands on it's own. Do good engineers and designers know who you are? How can you rise above the noise and get their attention so they come to you?

Are you or someone with your firm allocating time for passive search? If not, are you engaging with an external recruiter?

Do your employees, network, customers, etc... know you're hiring? Have you offered motivators which reward the act of referrals and the wins?

Try asking yourself the above questions to move the ball forward. If you have additional questions, I'm happy to chat via a call. Good luck!