What is the best way for a startup to attract talented back-end and front-end team members?
First, pay them properly. It’s a lot easier for a talented developer to chose a startup over an established company if they aren’t going to have to take a massive pay cut in exchange for equity (most developers are smart enough to know that most startups fail... especially developers who have been in the industry for a while). If you raise money from investors, this is what you should be raising it for.
Assuming you’re not asking them to take a big pay cut, attracting them becomes easier (that’s not to say it’s easy). Developers want to ship high quality code, quickly, without all of the political bullshit that you get in larger companies. They want to work with (and learn from) other smart people, and they want to be able to strongly influence both technical and product decisions. They don’t want to be treated as drones and have specs thrown over the wall at them. They don’t want to spend all day in meetings. If you pay attention to your company culture this is an area you can absolutely compete with larger companies on—make it more interesting and more fun to be a developer at a startup than to go and join a larger organisation.