Hi,
I am new to networking myself and from your description, it seems you are more knowlegeable in this area than myself.
Please note that I am not representing my company view in giving this advice. It is purely based on my self-study. You may choose to follow the advice or not and I am not liable for action that result from following this advice.
The advice I am about to give comes from self-study and little experience I have gathered at work.
Steps:
1. You need to require an outage to do this kind of work and this might be at weekend when the impact will be minimum. Before you implement this, make sure you have one experienced network engineer around during the outage time that you set aside for the work in case things go wrong.
2. You will need to do a design of what traffic each vlan will accomodate or which users need to be in each vlan.
3. Beware of VTP configuration when creating the Vlan and duplicating it across all your switches. Set only one or two switches as VTP mode servers (preferable the core switches) and any other switches as client.
4. Set a domain name and password when creating VTP this will ensure that when a new switch is added to the network, it will not distrupt normal operation on your network.
5. For security reason, do not use Vlan 1 as your native Vlan choose a random number.
I believe other people might add more to this list.
Once these fundamentals are in place, you can be rest assured that your implementation will go successfully.
Wishing you all the best.
