The 27-year-old has won three titles since September and appears well-placed to reach his first final at the season-ending tournament.
Murray begins with a clash against Kei Nishikori on Sunday and hopes a good week of practice holds him in good stead.
"Winning matches is how you play yourself into form and that's what I needed to do at this time of year," Murray said.
"This week in practice I've been okay.
"The practices have been hard - you're practising with the best players in the world so that's always tough, but it's good."
Murray will also play Roger Federer and Milos Raonic in Group B, with two of the pool reaching the semi-finals.
Murray has not beaten any of the top three - Novak Djokovic, Federer and Rafael Nadal - this year but feels it is something he has capable of in the English capital.
"I was getting asked earlier in the year about not beating someone in the top 15, then it was top 12, top 10, top eight, then top five, and now obviously this is the last step," he added.
"Maybe it's a big step but I've won against those players in the past and the more time I spend on court with them this year, the better for me next year.
"Whether I win against one of them this week or not remains to be seen but I'll give it my best shot.
"I still believe I can win against them and that's half the battle."