It is a fact of life for film users, if it was not for the those tiny light sensitive particles we would not have some of the world greatest pictures. All the same overly grainy negatives are a pain if you have not planned for it to happen it's a big let down. You must not forget that it is not all about the journey it is about the results as well and what looks like rubbish to you now. Maybe an inspired choice to others.
The fact you have a negative to look at is a result and something that will print and or scan. At one time grainy pictures were all the rage. Producing some wonderfully expressive images. Admittedly they are not everyone's cup of tea. In other words keep an open mind.
The object of developer is to bring out the latent image held in the emulsion. This is achieved by a chemical reaction, acting on the silver, producing dark areas where it is light and bright areas where there is shadow. The negative is reversed later with the print. There are three important things to keep at the front of your mind are: the development time, the temperature and dilution. It is these three factors that ensure the ultimate image quality when it comes to printing. Too short a development time will produce too thin a negative, like wise too long a process time will make the negative too dense, leading to very short and very long print times respectively.
Agitation is important as well and one of the most over looked parts of the film development, it can in some cases make the difference in how well your negatives turn out. As the developer interacts with the emulsion of the film, it vigorously attacks the silver it comes into contact with and becomes exhausted. By inverting the tank you refresh this action, producing evenly developed negatives. It is important to get this right. To little agitation will allow by-products of the process to build up, leaving pale-toned streamers as they slide to the bottom of the film. Likewise excessive inversions will produce currents in the developer, creating uneven development. Most process times allow for agitation.
The first thing to look at is the developer. This has the most influence over how your negatives will look. Before you settle on one in particular make sure you understand its attributes. On a practical note you also need to know how often you will process a film. If you are going to process a film every week or so then it may be better to use one in powder form like ID11 or D76. Or a one shot liquid for occasional use, like Ilfotec HC or Kodak HC110. I have suggested these developers because they are main stream fine grain developers. RO9 is not recognized as a fine grain.
Ilford ID11: A full speed developer with fine grain. Supplied as a two pack powder. Down side is that you have to make up 5 liters of stock solution. This then leads to question over it's keeping qualities. ( I have taken a year to use a 5ltr batch without any loss of quality) It can be used as one shot or multi use with allowance for depletion. ( I have only ever used as a one shot.)
Ilfords Ilfotec HC: A highly concentrated, fine grain liquid developer. It is suggested that this is the liquid equivalent to ID11.
Kodak D76: Fine grain developer recognized as Kodak's ID11. It has been reformulated as a one pack powder. The down side is that it needs very hot water to mix it easily.
Kodak HC 110: A fine grain sharp working developer. In a highly concentrated liquid syrup form. This is Kodak's answer to ID11/D76 as a liquid.
One more developer to what could be a very long list and that is:
RO9 Special/ Studional. These are the finer bred brothers of RO9 and Rodinal. They are very concentrated liquids with the good keeping qualities you would expect from this family.
It is the developer you choose that has the most influence over what your negatives and grain looks like. Inter mixed with the way you apply the agitation method you adopt and making sure that the temperature is right. Master this and the rest will fall into place. Yes you will make mistakes we all do even with years and years of experience it is all part of the rich tapestry of processing. It is and can be a pain when the results effect that special set of negatives. I know, it's that spanner that has landed with a big thud at times. The trick is understanding what went wrong, then put it right and move on. Now a days there is no such thing as a bad set of negatives - just conceptually challenging. You just have to look at all the apps you can get now that put back all things analogue photographers try to avoid. So what maybe unacceptable at first will change over time.
Really what I'm saying is to keep an open mind, the analogue process can, if you embrace it, give an unexpected creative lift to your images. Which today is more acceptable than it used to be.