Try to practice before you get there.
A key point in limited formats it's to know what the other play as soon as possible
and adapt your plays accordingly. For example if you know your opponents will Investigate in order not to play spells
and transform his creature, keep some mana open for an instant during his turn.
Also don't
forget to modify your deck between the games.
For example, if your opponent plays a lot of flyers, you can include cards like
Gloomwidow which is bad in the other case...
Watch your curve, don't
forget to add some bigger dudes even if they seem bad. Build your deck with a plan: control? aggro?
Sometimes you get a spoiler, but it doesn't determine your colours, you can splash for it!
Your deck must be coherent!