You'll do fine with just ridding yourself of the extra audio -
As Sly suggested, go to the extras first, change from automatic to custom and slide the bar all the way to the left. Do the same thing with the extras. THEN, lastly, change automatic to custom on the main feature - move that just slightly until it says 4300MB. You'll be set to go :D)
What sly meant was to open DVD Shrink, go to edit and choose preferences, and you will see Target DVD Size and a pull down menu, click the arrow and choose custom, to the right you will see a field with the number 4464. change it to the number ScubaPete suggested, 4300.
If you aren't trimming unwanted audio content, then you should take Pete's suggestion and take out the extra foreign language tracks and sub titles, and redundant English audio tracks. If you see an English track that says AC3 6 ch/5:1 and or DTS 5:1 then you should dump the one you don't need.
