"The rough is rough, so when you get in there, it's tough to get close to the pin or even on the green sometimes. Sometimes I got fortunate, but other times I was able to scramble and I think that's the most important thing around here."
The 18-year-old was second last Sunday in Phoenix in the Founders Cup.
"I can't believe our first major is already around the corner next week," Ko said.
"This is a great swing of events, the Founders Cup, Kia Classic and, obviously, the ANA Inspiration.
"It's a fun few weeks. I've just got to enjoy it. I haven't played as best as I think I could have at ANA, and I think my personal goal is to try and have my personal-best finish."
Shin took the lead after making birdies on five of her first eight holes and had a 7-under 65 to reach 10-under 134 at Aviara in the final event before the major ANA Inspiration next week in Rancho Mirage.
"It was a really good round," Shin said. "I hit great shots. I hit great putts. I had a lot of 6-footers for birdie, so it was a good day. ... I think I did a good job placing my ball in the right position and getting the right clubs."
The 23-year-old is winless on the LPGA Tour.
"I certainly see myself improving every year," Shin said. "I feel like in every aspect of the game I'm improving just a little bit."
Meanwhile, second-ranked Inbee Park and fellow South Korean player Hyo Joo Kim were 8 under. Park had a 69, and Kim shot a 66. Jessica Korda (67) and Sung Hyun Park (66) were 7 under.
Third-ranked Lexi Thompson (68), No. 4 Stacy Lewis (71), No. 6 Ha Na Jang (72) and No. 8 Brooke Henderson (70) were nine strokes back at 1 under.
Jang won this year in Florida and Singapore, and Thompson won in Thailand. Lewis has a 44-event victory drought that dates to June 2014.
Phoenix winner Sei Young Kim followed her opening 72 with a 74 to make the cut by a stroke at 2 over.
Last week, the fifth-ranked South Korean player matched Annika Sorenstam's LPGA Tour scoring record of 27 under, closing with a 10-under 62 for a five-stroke victory.
Michelle Wie also was 2 over after rounds of 70 and 76.
Defending champion Cristie Kerr missed the cut with rounds of 73 and 76.
-AP