So much good advice already. I’d add stay on top of your paperwork. It can be overwhelming on major cases. Little things that weren’t important before can surely become so.
Watch the women and the alcohol. I’ve seen a number of co-workers end up in a bind over those two things. Typically you have more freedom to screw up working plainclothes.
Don’t trust snitches or polygraphs.
Working investigations can be super rewarding! Congratulations and good luck!