Hi.
I have just come out of the other side of this. The outcome was fully expected, although not what I wanted. I would do it again.
What is your employer's policy? Make sure you follow it to the letter.
Mine was a v serious allegation and so was very rigourous. The organisation with prior form for the brhaviour so my experience may be different to yours.
You need to be realistic about what will happen. I don't say that to put you off, I just mean that you need to know what has happened previously when grieances have been submitted and know what is the likely outcome.
I knew based on my employers culture what would happen and sure enough, it did. I fully expected and prepared for that otherwise I would have been gutted.
I know the HR peeps on here will say each case is dealt with on it's on credit but unfortunately that is rarely the case.
Be careful who you trust. Understand that what people say to you isn't necessarily what they will say to the investigator. People look after themselves. I am still very hurt by a couple of people I thought I could trust and it became very clear they had either lied to me or the panel.
Know where you stand in the organisation. I knew who was viewed as more "important" which impacted on the outcome.
Prepare to be uncomfortable and paranoid. Depending on the organisation you may or may not get appropriate support.
Write everything down. Take in a list of questions/things you want to say to meetings so you don't forget anything.
Remember, you are not doing anything wrong (assuming you follow the policy and behave well during the process). The process is there to sort things out. Ultimately this is just a short term thing (although it might not feel like it). Try to keep it in context and remain dignified.