Should I be pinning high traffic pins from other boards to mine to give it momentum? Then remove it later?

Yes, you can pin high-quality pins from other accounts to your boards, but remember not to go overboard here. 5-10 other pins a week is good enough and the rest should be your own pins being shared to your own boards and group boards.
Also, removing pins does no one any good so we highly recommend not doing that ever. It is better to just archive boards if you are not happy with them.