If you are having trouble finding mouths with words to share, I would start by talking to the local party organization. This might be
The municipal party, if the district is within a single municipality in whole or in part. I.e. if more than half the district is in one municipality.
The county party, if the district covers multiple municipalities but is mostly or wholly within one county. Or if the municipal party is inactive.
The state party, if the district covers multiple counties.
The party organization should be in the phone book. Sometimes you might have to call the county organization to get contact info for the more local organization.
One of those should exist and should be able to put you in touch with people who have either managed a campaign previously or been prominent enough that it makes sense for them to be promoted.
Sometimes they may not want to work with you. For example, if you are challenging an incumbent in a primary, the party may not want to encourage that. An alternative then is to canvass the local party organizations. So if you're running statewide and can't get help from the state organization, ask the county organizations to let you go to their next meeting. Even if the organization as a whole doesn't want to work with you, you may find that individuals will. This is more work, so it wouldn't be my first choice. On the bright side, meeting with the local organizations is something that you would want to do anyway. It's just that normally you'd pick or hire a campaign manager first.
Another possibility is to call previous candidates that you liked but who failed. Ask them for advice. Successful candidates can be hard to reach without party support, but failed candidates are often grateful for the attention.
If all else fails, find someone that you trust to run the campaign. This could be a family member, friend, or long time employee. Even if that person only covers the role during the primary, that can take some of the work off you and allow you to concentrate on campaigning. And if you win the primary over a party-preferred candidate, the party will be eager to work with you in the general. So you can bring in a more experienced person then.