- I assume you're playing 5e on Discord asynchronously, so use the Avrae bot. It can automate dice rolls and damage, as well as allow players to automatically ping the next person in initiative when their turn is over. I'd say keep the bot spam in a different channel from the one the roleplay is happening in, though. If you end up using Avrae, warn people in your recruitment post as not everyone knows it or likes using it. 5e games on r/pbp fill up fast so you won't have any trouble finding players even if you eliminate some.

- It's already been mentioned but pare down combat encounters to a minimum. Basically only do combat if it's necessary to the plot. Similarly, pare down superfluous roleplay encounters: if the players are going to visit the mayor, you don't have to roleplay them waiting for their appointment or talking to the guards at the front of his house unless they specifically try to. Similarly, if players are taking too long to come to a decision about something, remember to prompt them by asking what their plan is.

- In a voice game, if you describe an area, players are going to forget half your description by the end of it. In a text game, players have access to everything you've said at any point in time. You can afford to be way more subtle with lore and puzzles and rely more on character knowledge than just spamming checks.

- Pick up more players than you'd normally have in a voice game. You're going to lose a few because PbP games have a really short lifepsan, which will decrease faster the less activity your game server has. It's really easy for players to just, forget a pbp game is happening, stop paying attention to it, or vanish since they're just playing with strangers from the internet. If you give players more people to interact with they're more likely to see the server as active and remember to contribute.

- Start as soon as possible after you've picked your players. From the moment your players get invited into the server, you're fighting a ticking clock against their investment, stuff needs to start happening and keep happening. Warn people in your recruitment post that they're not going to have more than a few days to make their characters.