I don’t have an OT, but I was reading how VoltageCtrlR processes his samples. He said…
I eq my samples a bit going into the sampler, then I eq every track on the Octatrack, then run the Octatrack out through master bus compression while recording. Then I just do a little mixing / compression to the stereo 2 track master. It’s easy to forget because the outputs of the OT are always going into my secret stash of analog outboard gear…
Does the OT have an equalizer for every track?
The EQ could be one of the effects assigned to one of the two effect slots on each track, yes.
The OT has amazing flexibility like that.
Edit: changed machine to track
OT has two band parametric eq (each band can be set to low shelf, high shelf or bell with control over frequency, gain and q), a DJ style kill eq (three bands) and it has the base width filter.
If you need more than two effects you can use neighbour machines.
I mix when everything is how I want it.
If I mix in the OT I do what I do in my DAW, record my various tracks and then EQ them.
I found much more convenient because I don’t have to limit myself to use 1 FX or to use a track as neighbour one.
But you surely can apply EQ to everytrack and if you have track 8 as master of course you can apply a master comp+EQ
That is exactly what I do. Especially on kick drum eq room for bassline or just to remove some unwanted rumble. Also with hihats to remove build up of harsh frequencies.
You can also create a notch filter and if assign the frequency to a LFO you get a nice speudo-phaser without the stereo-spread.
Next thing is hi-passing for cleaner low-end.
In the end it follows the same techniques used in mixing, but with one major drawback: you loose one fx-slot per track and with it a good piece of the creative capabilities. The questions is: cleaner sound or another delay/ darkvervb or what ever.
For even better sound I take the time and prep my samples and loops in the DAW to preserve FX slots on the OT.
Just use what you want, sample your track and then apply EQ. Why limit yourself? 
Totally agree, but also I don’t like to have endless iterations of the same sample/ loop on OT.
But yes, I mostly take the time and do some clean-up before I upload to the OT.
Don’t listen too much to what I say as I’m only working with the OT for half a year. But here’s my way of working:
I don’t work in a DAW, because I do this for fun instead of professionally or for a paying audience. So EQing in OT itself is good enough for me. I basically always use the Filter on OT’s first FX slot. It’s great for two purposes: it’s nice for basic EQing, with a low and high pass (base and width) with resonance that you can set to either one or both. Second, it’s super musical, so apart from basic EQing it’s great to spice up, mangle, or alter samples drastically, either tweaked once for the sample and left alone or to tweak live for lots of movement on the sample. It also has a nice and simple attack&decay filtermod-envelope. I think it’s probably the most used FX type by OT users, and definitely for a reason.