From an engineering - rather than a musician - point of view, if you have only one eight-track deck, you can do just what we did when 8-track first came out in the late 60's but consoles were still 3-track.
For the single 8-track deck without having to bounce to the 2-track and back, there's two main ways to do this. The first few steps are the same in both though.
1. Lay in a click track
2. Lay in a scratch guideman's track for the soloist to follow.
3. Lay in a scratch soloist's track for them to follow later when cutting the final lead.
One Way:
If you need to start the conventional way with drums, bass, rhythm guitar and piano and are fond of having a half-a-dozen mics on a drum kit by itself for example, then you'll just have to mix the drums
(or whatever) to a maximum of three tracks, mix down to mono on an empty one and proceed conventionally until you have six of your eight tracks filled, including the ones for scratch soloist and, scratch guitar/piano (guide instrument).
Now mix that down to two tracks as a Basic Tracks mix, leaving your scratch soloist's track, and your scratch guideman's track alone. If you want to re-use the click track being you have the guideman's track and the scratch soloist's track there, you can try that if you want, just remember you can't go back and get it later if you need it.
SO now on your 8-track, you have
1. mono drums,
2. mono bass,
3. mono guitar,
4. mono piano
5. scratch soloist
6. scratch guideman
7. blank
8. click track
So you take the first four, mix that to mono, lay it on 7 and start over, (keeping your scratch soloist and scratch guideman track through as many stages as you need).
So now, getting ready to go into your second stage, on your 8-track you have:
1. blank
2. blank
3. blank
4. blank
5. scratch soloist
6. scratch guideman
7. the mono mix of all your first four tracks
8. click track.
Now, do it all over again with your NEXT set of overdubs, mix the overdubs to mono and lay that on 1.
Do it all over again and lay the next one on 2.
Do it again for 3 and do it again for 4.
Now you have five sets of mono mixdowns of elements and you still have your scratch guideman and scratch soloist track as well as your click track.
Then you can come in and have your guideman re-record their final production track over the click track.
Do the same thing for your soloist, having them record over the guideman's scratch track, which leaves one open in case you need a harmony track to the lead or some other overdub at the last minute you just Have to Have.
NOW you can mix from the 8-track to Stereo, placing the various mono-mixdowns of your various recording stages in a pleasing arrangement from left to right, balancing the now-mono elements as best you can, leaving of course the soloist in the center surrounded by the other elements.
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Other Way:
Record from back to front, i.e. start off with a stage of recording containing the least-audible elements in your production, occupying a MAXIMUM of three tracks apiece for each element or group of elements.
Which means before you do anything, since you can't start off with drums and/or bass like you usually do because those are prominent in a great number of productions, is you will need to lay a click track on 8.
So after you lay in your click track to keep you on-tempo throughout, now you have to find out what necessary element is going to be the farthest back in your mix, Back in the day, we'd always record a scratch piano (or guitar) on one track so the vocalist or lead instrumentalist could keep their place, and then record a scratch vocal (or other lead) discretely on its' own track first, after laying down the click track.
Then you lay in the second-to-the-most-buried element in the first stage of your mix and so on and so on and so on until you have 4 of your 8 tracks filled, keeping your scratch piano/ guitar and scratch vocal/lead instrumentalist for now.
Now, take those tracks (i.e five for your First Stage elements, leaving out the ones for the click track scratch piano or guitar and scratch vocal or instrumental soloist) and mixdown, i.e. recording over your scratch piano/guitar and scratch lead (or do it the other way around) into what we'll call here a 2-track Basic Tracks mix (even though really its the REVERSE of a Basic Tracks mix being there's no bass, drums, guitar or piano in the mix).
So now you have a 2-track reverse-of-a-Basic Tracks-mix on two tracks.
If you still need your click track so you can lay in your drums and bass later, keep it on its' own track.
Now, repeat the process, a maximum of three tracks at a time mixing down to two (or one) until you are done with however many stages of recording will fit on your tape, re-cut your guideman's final performance track over the click track and record your soloist's final lead track over your scratch guideman's track, use the last one for whatever you want and mix down.
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FOR TWO EIGHT TRACK DECKS:
Do the same, except you get TWO passes of 3-track sessions on the first tape, plus your scratch lead and your scratch guideman.
Mix each of those two 3-track sessions (1-3 and 4-6 on the first tape) down to mono and lay them on 1 and 2 of the 2nd 8-track.
Repeat with two MORE 3-track sessions on the SECOND eight track, and then mix THOSE two three-track sessions to mono and layback them to the FIRST 8-track along with the one-generation-down first stage mixed-to-mono tracks you imported from the first 8-track.
So, now you have four tracks used back on the first 8-track.
Repeat again with another 3-track overdub session leaving you one open for another sideman.
Repeat the process back and forth between the 8-track decks until your production is complete.
EXTRA HINT:
If you bump up the treble a LITTLE BIT in your first few stages that will be getting tape hiss from them incorporated into their mono (or stereo) mixdown of elements and bounced back and forth from one deck to the next, then upon final mixdown, you can take the treble level down a little bit for those early-stage elements and the generational hiss problem won't be anywhere near as evident.
