The recent wedding cake I did was my first time making and piping with Royal Icing. It didn't look too bad, especially I made the icing too firm to begin with and then thinned it out to make it easier to pipe, but no matter how hard I tried, the icing still had little peaks at the end of the scrolls and the dots as well. 

You can see it more clearly on the middle image here

http://www.cakecentral.com/gallery/i/3341385/first-wedding-cake

Is there a technique to preventing this? I tried to do it with the nozzle held in and stopped squeezing, also pulling away as I was squeezing, but both ways seemed to make it peak up. I'd like to be able to get the hang of this for the future.

Do not pull away from the cake, but pull sharply to the left or right to "slice off" the peaks. A little powder sugar on the fingertip to go back over any "tips" works too.

I use a damp paint brush to pat down the peaks every so often before they dry. Nothing worse than a nipply-cake!

Yes....I agree...  ;)

Nippte cake - that's hilarious. 

Lovely cake! You did a great job. 

As said above^ you want to cut off the and rather than pulling it. I find making a little swirl motion on the spot before removing the piping tip helps. And in the end the wet finger ^

I would also use a guideline for piping straight.  Noticed a little wave in your top tier. Like for example a 3" paper ribbon that you can remove after you are done. 

Not saying I'm a pro by all means. And no offence!  Just noticed it...

What winniemog said.   You'll also improve with practice.

Very impressive for a first wedding cake!  Congratulations!

I do a swirly type of motion, but I like the slicing motion as well.

I do a swirly type of motion, but I like the slicing motion as well.

Nipply-Cake lol yes I am guilty..... Thank you for the this. I need to practice my piping!

if you get your royal the correct consistency you can pipe dots all day with one squeeze that will form perfect little orbs - it's awesome fun - add gum Arabic to your royal and they will be shimmery too

Looks like I need to work on the consistency then. It was the first time I made it for piping and it went VERY thick at first until I thinned it down. Guess it's something I need to practice with! :)