Q:

What is the meaning of the expression "コツがいったり"?

I found the expression "コツがいったり" in a tourism advertisement for the 金閣寺 in 京都:

シャッター押すのをやめて
  じっと、まぶたに焼きつけています。
  しっかり見る。しっかり感動する。
  簡単にみえても、案外、コツがいったりするんです。

From what I can see via web searches, it doesn't appear to be a particularly uncommon expression, as it is also used in lots of other sources, but I can't find any definition of it in any dictionaries.
I'm familiar with the 〜たり（する） structure, the confusion is in regards to the コツがいった. I assume that "コツ" is the same word that means "knack", "essence", or "technique", etc., but I'm not sure of the verb (if it were いる, wouldn't it normally be いたり?), and it seems to be a set expression based on its usage.
Thanks for the help!

A:

You are looking up the wrong 「いる」 ("to be", "to exist").  Past tense is 「いた」.
The 「いる」 in 「コツがいる」 is 「[要]{い}る」 ("to be necessary").  Past tense is 「いった」.　 「コツがいる」 is an extremely common phrase meaning "to need to get the knack".
「コツがいったりするんです」 is a softened and informal expression roughly meaning "You kind of need to get the knack of it."
Knack of what?  It is to be able to do the things described in the first two sentences --- "Stop taking pictures and get the scenery burned into your memory.  Look hard and get blown away!"

