this is one of those how many stars are there in the sky questions.
this is what seperates the real high end audio engineer from the rest of us. ie...what to use and when. and relates often to how you want the final mix to sound. and what the song needs.
in the tracking stage you can lay down fx like in the old days when they had
fewer tracks to play(problem is YOU HAVE TO COMMIT EARLY ON) with like they used to have with 3 track machines.
or - after the fact. at mixdown. you didnt say what effects you have ?
all i can tell you is how i would use this limited number of tracks.
i would have the band play live and get a good stereo bed track of drums, bass, and rhythm guitars recorded to 2 tracks of the 8. this leaves you with 6 more tracks. there is a TRICK you can use to get more tracks.
when you have filled up the 8 tracks you could mix to two tracks in stereo
and record the mix in stereo on a pc.(assuming you have say an audiophile level sound card). then send out the stereo mix from the pc back to two tracks on a fresh reel of tape and add 6 more tracks.
thus you could get a pretty sophisticated production this way.
another way is sometimes you can find used tascam 8 tracks for 250 bucks if you search. thus you could then build up 8 tracks on machine 1 (your current one) then mix to stereo on two tracks of machine 2 and add six more tracks.
if you detail your equipment more thoroughly i'll try and make more suggestions. frankly , now i use a pc and can do 48 track recording on it.
might be something to consider for the future.
peace.