Well as most basic thing, you should post your phase to Phase List.
Find some friends who can do modding for you. Especially during active times you won't be able to handle it yourself at all.
Find a decent, sustaniable, and improvable phase idea and sitck with it. Regularly adversite your phase in-game, make sure you find some strict mods. There's a scale between a completely wild, zero quality control lolrp phase and completely strict, unforgiving elitist phase. Less quality control will surely attract more people, but will cause you eventually get trolled and smacked down in forums.
Research some phase building tips on forum. I can't give you any decent advice on it since It's a very detailed topic itself, bothtechincal and aesthetical. But for starters; don't rely on custom object patches so much (maybe except montytiles) and don't go overdetailing, which cause fps drops for the people in your server.
In any case, do NOT let Erp'ing (doesn't matter private or public) in your phase. Don't even imply any "weird" romance statuses between the mods or other characters. People actually hate that. A lot.
While mods do "Quality control" for you, you should keep them in check as well. Be noncontradictory. If you let people go around as strange exotic races while you claim a strict-style rp, that will surely draw reaction. Make sure each of your mods actually follows the rules you put and don't hestiate to fire them if they cause trouble with phase's reputation. Btw ban exotics while you're at it and be strict about this.
Remember while you don't need any excuse to ban people out of your phase, you have to contact these inviduals first about it and kindly ask them to fix. Don't get into any argues with them, simply state the problem and ban them if they persist. Of course, that doesn't apply to players that break rules you clearly stated in phase advertisement. Also It's very important to take action against trolls before they blend into the phase events. Nobody likes to see someone got banned middle of a IC conversation or a fight. If this happens, try to remove them ICly. Always keep in mind you're a freakin' God there.
Since your phase will be open all the time, It will be open to all kind of trolling. Make sure your phase is a retail one. Shut down all kind of commands that let trolls abuse your phase like .gps,.cast and .learn (There are subcommands for those in .phase command).
"Automatize" your phase as much as you can. You should add map tooltips, Gobject with some OOC guides about your phase, NPCs with dialog & gossip options. Let AI to do small things like selling a drink or welcoming the guests.
These are few tips I can think of. I'll let you know my phase hosting experience isn't very long and I might be wrong at many of these.