Hi Youngster,
Sorry mate but is an affliction for life, once it gets into your blood you are hooked for life.
It will depend on what variety you have the different preparation you will need but they are all pretty similar and there are some basics that apply to any or every breed.
Preparation starts long before a show in the mating/hatching/rearing, get these right and you are well on your way.
Decide some time in advance where you are going to show.Get a copy of the schedule and mark it with what you want to show, select a small team of your best , no point in entering everything, better to enter a few to start and do it right than enter a heap and only half prepare them and be disappointed in the results.
Approach the day or week-end as a fun experience where you will learn and interact with others that share your interest, listen a lot and say say little, you will be surprised how much you will learn and how helpful the experienced exhibitors will be.
Enter early to avoid the entry filling and being unable to get yours in, keep a copy of what you have entered, makes life easier to know specifically what you have to prepare and the Show Sec will appreciate you being prepared knowing exactly what goes where, also a help if your entry has gone astray and they need to make last minute changes to fit you in.Most if not all shows are entered in duplicate, one copy is returned to you when you arrive with pen numbers included and the other kept by the Sec to pen you out at the end of the show.
No entry at penning time will be accepted with lice, scally leg or any respitatory or infectious disease, so all birds need to be checked for these and in good health.
They will need to be in good condition but not over fat, clean and feather in good condition, not broken or in a moult etc.
Feather legged varieties will need to have the foot feather in good condition, keeping them on clean bedding or sand will help, a wash with warm soapy water and soft toothbrush (rinse well) a couple of days before might be needed if they are dirty, nails will also need to be trimmed if long on mature birds and kept on soft ground or deep litter.
Light coloured or white fowls will benifit from being out of the harsh direct sun which can bleach and yellow the colour.
Legs generally will need to be washed with a soft cloth and soapy water even gently with a soft toothbrush again to remove dirt from between the leg scales, combs need to be cleaned in a similar manner.
On the day of the show a soft woolen cloth in a jar with some light oil is handy to wipe the legs and comb, removes dust and just gives them a healthy glow, applied as you take each bird to place it in the showpen.Likewise a piece of silk (silk scarf)or milenase(old petty coat if mum still wears them, she will know what it is) handy to carry to smooth the feathers (grooms them) and removes any dust, shines and polishes the feather lifting the shine and lustre of the feather.
Pullets or hens on point of lay give a lovely healthy glow, if in full lay can appear loose and baggy in the rear end , some breeds this is not a good look (even penalised) but with others deepens the body and is of benifit.
Hope this helps and most importantly enjoy the experience and day out.
Good Luck.
Be gracious in winning and losing, you will win a lot of new friends if you do, win or lose if you have enjoyed the experience you have had a good day.