The key is to take it slow. Seriously to many folks are so keen to get started and get their new system up and running that they rush and make basic mistakes.
Methodical and careful. If at all possible wear an untistatic band.
Visulise your build and the sequence of your build before you start. Think about cable management before you start and not as an after thought. So look to layer your cables under the motherboard for USB headers and sound.
But over all just enjoy the process.
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