optimize SQL querys and php code

Need someone to go through all my querys and related php code and finally rewrite to optimize the speed of showing data. There is about 300 rows of querys and php code at the moment in database there is about 120000 rows with multiple columns spread on multiple tables ( but when finnished with the database work it would hold about 100 millions rows spread on multiple tables ) So i need the person that takes the job to be really good of making big databases really fast in querys and show data. example of sql query to rewrite: $sqlexample = "select * from t1 where [login to view URL] IN (select exampleid from t2 where show='yes' )"; Just ask in clarafication board so all can see my answers on this job