Samoa clearly has been rebuilding through the former New Zealand coach's first season at the helm.
Their best finish has been quarterfinal places in just three of the tournaments and they currently lie 13th on the series ladder.
When Tietjens first took control during January's Wellington Sevens he indicated the team's defence needed to improve.
He said is still a work-on.
"Defence is a massive part of sevens rugby these days and we've put some good systems in place but obviously we've been missing and falling off early first tackles," Tietjens said.
"It's mainly a technical issue and getting a shoulder on, sometimes planting and getting beaten on the inside shoulder.
"We have put a lot of work on that certainly in the last two weeks and certainly looking for a massive improvement going into Paris," he said.
Tietjens said the team still needs to approach paris with confidence and belief.
Samoa won last year's event, defeating Fiji in the final.
The two will again meet, this time in the opening game of the tournament.
Tietjens said they can take inspiration from last year even though it is a new team now.
"We're just looking at every game this coming tournament as a final and still look for that real improvement that we are seeking," he said.
"Great to go in on the back of last year but we need to get up and perform like they did last year and ours is a new team and we certainly be looking for every game to be playing very, very well.
Samoa will also face Australia and Russia in pool play.