Notation conventions for superscripts and subscripts I want to establish a consistent notation in my work, however, I struggle with the correct notation when more than one condition is present.

First, I am wondering what to put in the superscripts and what in subscripts. 

I figured that the following is often in superscripts:


denoting that something is optimal, e.g., $p^*$
describing that something is a special condition, e.g., $p^{\alpha=1}$
denoting critical values, e.g., $b^{crit}$


I figured that the following is often in subscripts:


denoting an individuum, firm, combination, $p_i$, $\pi_j$, $p_{ij}$
numbers of different solutions $c_1$, $c_2$


Some cases were not very consistent


"states" or strategic alternatives are sometimes sub/subscripted, $\pi_M$ and $\pi^M$


So my first question is: Is there a rule, guideline or best practice for what to put where? 

Second, I am wondering how to correctly write combinations of different subscripts or superscripts. 


As an example, one could take the first derivative of the optimal price. Would that be ${\pi^*}^{'}$  ({\pi^*}^{'}) or is it better to write $\pi^{'*}$ (\pi^{'*}) or $\pi^{*'}$ (\pi^{*'})?
Similarly, how do we combine for example special conditions and optimal values $p^{\alpha=1,*}$ or $p^{*,\alpha=1}$, ${p^{\alpha=1}}^{*}$ or ${p^{*}}^{\alpha=1}$?
Where do we place numbered solutions for specific conditions when both are used in subscripts (e.g., $c_1$ in $\pi_M$)? is it  $c_{1M}$, $c_{M1}$,  $c_{M,1}$,  $c_{1,M}$?


So my second question is: Is there a rule, guideline or best practice of how to combine different subscripts vs. superscripts
This is only partial answer since your question is quite broad but in my work I had similar problems. 

When ti comes to optimal values and derivatives I choose to use Leibniz's notation as it does the job quite nicely:

instead of writing this $\pi^{'*}$, I would write this $\frac{\partial \pi^*}{\partial x}$ or if you like it more  $\frac{\partial }{\partial x}(\pi^*)$, sure it takes some time to type out but in my humble opinion it looks quite good. I try to use Leibniz's notation any time there are some other superscripts or subscripts (as with multivariate function even derivatives with subscripts can be problematic).

For conditions consider maybe notation borrowed from statistics so instead of $p^{*,\alpha =1} $ I would use $[p^*|\alpha=1]$

Regarding those numbered solutions, I was once told by older scientist, during my internship at one research institute, that when  you have one letter subscripts you can just put them without comma but if one of the subscripts has multiple letters always put comma so for example $x_{itj}$ is fine but when I need to put $t-1$ I would put it as $x_{ij,t-1}$ (to be honest I have no idea to this day if there could be some issue with this but so far nobody complained - not even at  conferences/workshops where I was presenting my work, nor any referee - although I dont have that many published work yet as I am very young researcher, so maybe take that as a caveat regarding my suggestions).