Campden tablets help avoid oxidation, although I find if you rack carefully by pouring down the side of the FV you will be fine. Also eliminate any un-necessary racking in the process.
While you have live yeast it's not much of a risk, as the yeast can eat it.
When the wine's done and you rack to stabilise and/or bottle, use a crushed Campden to take care of any oxygen you accidentally introduce.
Don't leave too much headspace in bulk maturing vessels or bottles.
If using real corks, store bottles on their sides to keep corks wet so they don't shrink.