Lambert has signed defenders Jores Okore and Antonio Luna, midfielders Aleksandar Tonev and Leandro Bacuna, Danish striker Nicklas Helenius and Norwich goalkeeper Jed Steer so far this summer.
And the 43-year-old is hopeful the new faces at Villa Park can help the side build on a frustrating 2012/13 season.
"Having genuine competition for places is really healthy and, in fact, vital for any club that aspires to bigger and better things," said Lambert.
"For instance, Antonio Luna has come in and he will augment and enhance the defence and give us some more options there.
"He's played about 70 games in Spain and we all know the standard of football in La Liga.
"We know that defensively we need to improve from last season, overall as a team, so that's good.
"Bringing in Jed will also add to the goalkeeping department and helps with everyone pushing one another, learning from one another and making everyone better and wanting to improve.
"You want competition for places throughout the team, which is something we didn't have last season."