Re: Improv, Support, and Lead Alto
You might be playing loud, but maybe your sound isn't very big. There's a difference. You can hear Joe Lovano play pianissimo from across a crouded concert hall, cause his sound is big, just not necessarily loud. As for sight reading, just do it. The more you do it, the better you'll get at it. You probably struggle the most with sight reading rhythms, right? Most people do. Get your teacher or band director to get/make you a ton of rhythm sheets (a buch of rhythms written out on the B line with no note values) and start sight reading those. Also, take a book of etudes, and play every one every day. That way, you're working on everything an etude study gives you, and sight reading.
Improv - you're prboably good enough for first alto. Lead tenor usually does most of the soloing. A drummer friend of mine refers to lead tenor as 'go tenor'.