First would be find a good local ring craft class, a good one is worth travelling for, I tried 3 before finding a 4th that fit the bill perfectly
Get lots of help off anyone who will give you any (lots and lots of forum peeps are always willing to give advice etc) on anything your not sure of.
Keep it fun as half of it is your dog enjoying what its doing

Keep training short and sweet i.e. if your stacking just do a tiny bit and leave it so its always fun.
Before entering your first show stick another post on here for peeps to give you an idea of what to expect etc, I did a couple of open (smaller) shows with Kodi but then didnt show for some months and dove straight into the WA champ show so I would say do what you feel is right for you at any point. You will find you can make lots of friends showing and they will offer lots of advice if you just ask
Most of all just try and enjoy yourself....best of luck with it all!!