I am glad you have found our articles on Sax on the Web helpful in your playing.
Tim's exercises are not easy. You should begin VERY slowly. Go no faster than you are able and still play the passages evenly and smoothly. Practice these with a metronome.
Also, let me ask... do you have a community band where you live? A concert band for students, amateurs, etc? If so, join such a band right away. Your reading will improve much faster if you are playing with other musicians. In the U.S., you can find such bands through the Association of Concert Bands.
Many of these community bands have both concert and jazz bands. Some have further offshoots, such as sax quartets, clarinet quartets, Dixieland, and other small combos.
When playing by yourself you can easily get into some bad habits... habits that will adversely affect your playing when playing with others.
(1) You make a minor mistake, and stop, go back and try to correct it, to make it perfect.... This does not work when playing with other players, as the band or orchestra is not going to stop just for you. When you make a mistake, keep going! That moment in time can never be recaptured.
(2) You may not keep a steady tempo... speeding up during easy passages and slowing down when the music gets difficult. Steady tempo, and the ability to synchronize your playing with others... that is, being precisely on the beat, neither ahead or lagging, is very important.
(3) You may not play in tune. When playing by yourself, you have no pitch reference.
All three of these problems may be corrected by playing with other musicians, OR...
Go to Amazon.com, search and order some play-along CD's from the Jamey Aebersold CD/book sets. Perhaps local music stores may be able to order these for you. These are excellent... you will find everything from old "standards" to rock to jazz to blues. My favorites are the Body and Soul (vol. 41), Ellington
, Ballads, and Blues in all Keys CD sets.
For the classically inclined, many solos are available with playalong CD accompaniment.