Reaction and reactor parameters
As much as possible, you should describe both your reaction parameters and your reactor parameters.
Your feed compositions, temperature and pressure are essential descriptions of your setup. Ideally with temperature, you measure a temperature most representative of the reaction, rather than the temperature of the reactor exterior. Since this is a flow reaction, you should also describe your flow rates of the feed materials.For multiphasic systems, the startup procedure can affect which phase is continuous and which is disperse. In regards to your reactor there may be additional parameters such as stirring speed, or conditions associated with for example light (photochemistry) or electricity (electrochemistry) that you need to report. Finally give some thought to describing the reactor - the volume, geometry, mixing elements. Of course you may have additional measurements e.g. within the reaction (e.g. pH, composition) that you take to help you determine the reaction itself.
For single phase reactions, the flow rate of material is enough to specify the hydrodynamics of the reaction.
For liquid-liquid reactions, the way you start the reactor, alongside the flow of material, defines the state within the reactor. For a liquid-liquid system, you can have an organic in water phase or a water in organic phase - what you end up with is due to the relative rates of flow, the startup of the reactor (you generally fill with your continuous phase first) and mixing conditions. Additionally, surfactants can change this behaviour.
For gas-liquid reactions, the gas will ideally be small bubbles within the liquid, giving good mass transport. The gas will occupy a certain volume of the reactor and the liquid the remainder. Knowing the volume fraction helps you establish the residence times of the two phases.
For solid-liquid reactions, the quantity of particles in the reactor is important. Ideally for a well mixed reactor, the particles remain well suspended, but if there is potential for particles to collect in dead-regions in the flow, there maybe pockets of solids. Mix well and this problem goes away!
Of course, it isn't always possible to collect all this data, but at a minimum reporting carefully what you have set up and how you have run the reaction together with visual observations will allow further study if, for example, you wanted to scale-up.