Tourney's are fun, a few rules I live by when go:
1. Before begins:
My entire army is
WYSIWYG and on correct base sizes.
If I run say different chapters etc in the same army, I always make sure they are totally different colours to each other (makes it easy for me and my opponents).
I always carry super glue, blu-
tac (think maybe called poster
tac in your country, just incase models break), water, snacks and some spare models. Some tourneys require other things just make sure before the event.
My army list is printed in a clear format and 1 for each opponent. I also have stapled to this all the weird rules,
FAQ etc and all my stratagems for my army. Moreover, I ask them if they have any questions after they have a few minutes to flick threw (for example if I am Harlies I explain my Masque form, relics etc and implications of some strats to my opponent if they don't know).
I have all relevant rule books.
2. Gaming:
You are there for competition, but to have fun, treat it as such. Don't be the dick of the tourney.
If you start thinking in an aggressive manner, it will make it crap for you and your opponent.
If you opponent does something you think is wrong (they might not know), don't be "Bloody hell that's bollocks, you can't move like that!". Be more like " Hey mate I don't think he can move like that, lets check it over in the rule book" etc... or "Maybe we can ask a judge if that's correct, just I swear it is different now days".
It's a game about moving models around on a board not about life and death.
3. Transport:
Before the tourney practise transporting your models in whatever case/s you use a few times before (either going to work or whatever).
If it's to expensive for you to go and is driving, look for car pooling, shared accommodation etc. Sometimes some people that live near an event will put you up for a night or two at their homes if they are going just ask around etc.
A few tips.
Number one is don't be a dick. You can be competitive but still be awesome