Greetings,
A good teacher is good to have. They can get you going in the right direction. Practicing the scales and arpeggios with a metronome slowly.
Long tones to help to develop your embochure and sound.
You may want to check out this site:
http://www.saxlessons.com/
He has some good stuff. Evan Tate is pretty cool too. He has some online stuff that's great. He's online in Germany. He's a great educator and has some ebooks that are good. Evan Tate:
http://www.evantate.com/ You can download his podcasts. They usually come about every week or so ........ he's very informative from a jazz standpoint.
That Yamaha looks like a good horn. I have a friend that bought a Yamaha a few years ago. I played it and it played well. Nice sound.
Looks like that Yamaha Yas 23 runs for about $1700 from this link:
http://www.wwbw.com/Yamaha-YAS-23-Alto-Saxophone-i17490.music
I know a lot of these saxophone afficianados frown on the Asian market saxophones but I have played some and some of them play very well. The prices are very reasonable. I remember what they were saying when Toyotas and Hondas were coming out. They improved very fast. It seems the same thing is happening in the horn markets. The orientals get the idea and just keep on improving till they get it right. Look at the Koreans and the nukes ....... took em a while but now they are getting some attention for sure
There are a lot of links for Saxophone players ...... I will see if I can dig em up for you.
hope that helps
donald manuel