Having slipped to ninth of the eleven teams in last year's constructors' standings, former multiple title winner Williams has invested heavily for 2014 and now features highly-respected names like Pat Symonds, Felipe Massa, incoming sponsor Martini and Mercedes power.
Insiders believe the new FW36 appeared reliable and competitive at the recent Jerez test, and according to Bottas the Grove based team is in high spirits heading into the second test this week in Bahrain.
"It's a good feeling to see that your team is in such good spirits," he told the Finnish newspaper Turun Sanomat.
"The feeling now compared to this time a year ago is a completely different category.
"Now the spirit is really high, especially when all the major departments have new staff on duty.
"They've come from a variety of top teams like Red Bull, Lotus and Mercedes, so our experience has increased.
"Things have gotten better since Pat Symonds came in -- he put things on a better basis and hopefully it will show with the performance of our car as soon as possible," said Bottas.
Bottas also sounded delighted with Williams' new engine partner, with the team having switched from the now-troubled supplier Renault over the winter.
"From what I could see at the Jerez test, I'm happy that we chose Mercedes," he said.
There are fears, however, that the new and highly complex 'power unit' technology, and the severe fuel limitations, will detract this year from the actual driving.
"The fastest driver will not win this year," Toro Rosso engineer Xevi Pujolar told Spain's El Confidencial. "Now it (the winner) will be the one who is fastest in the most efficient way."
Bottas agrees that technology will play a much bigger role in 2014, but: "Driving skills will still be the most important thing."