All batsmen have nerves when they first stride to the crease if it be opening the innings or batting down the order. My advice is to get a routine my routine varied only slightly depending on where I would be batting in the order but from the moment I walked on to the park it didn’t change.
Firstly was to play a couple of forward defensive shots as I walked out.
Second was to meet the batting partner where you get advice on what they might have seen while they have been at the crease and depending on where the games was at would quickly make plans or reinforce coaches or captains plans.
Thirdly would be to take guard mark my batting line I would then step back look around the field noting where the field was positioned where I could find a single to get off the mark, where my favourite shots covered do they know where my weakness are do they have them covered.
Fourthly would be to take 3 deep breaths inhaling through my nose exhaling through my mouth I found this calmed me as I went into my stance I would become focused on the ball in the bowlers hand can I pick up what he is about to bowl to me.
As the bowler runs in I tried to make sure my head is still eyes level shoulder squared. as bowler reaches half way my thought is play in the v ,wait for the ball that is mine to get off the mark, as much as I loved to pull, hook and cut they where shots that would also get me out (so I am putting them away till I get off the mark unless the game needs it) not going to play these shots till I have been at the crease for 4 or 5 overs.
Now I am not saying my routine is right for everyone I know players, who would sweat on the short ball play slashing hook, pull and cut shots to get themselves off the mark from the first ball they faced.
What I am saying is know your strengths and weakness in your batting have a routine that you feel comfortable with now all that said remember your going to get a ball that takes your wicket at some stage it could be the best ball ever that would get Ricky Ponting out or it could be a ball that you play the wrong shot at the thing is if you can learn something from it then you will improve.