Well, I can't answer for private servers, as I've always played on officials. Even then, I will give some tips that might work for you.
If you don't want to get banned, don't bot, simply as that. I've quit counting how many bots I lost after my 30th or so... Losing a bot doesn't make me mad, much the opposite. I open a can of cola and think on what it went wrong, then I start to work on it. Believe me, nothing in this game is more satisfying then avoiding a GM sucessfully. As the mighty botter Keko once said, I don't bot to play the game, I play the game to bot.

Nevermind...
Start slow. Don't obsess on greed. One account well configured, well equipped, well organized, will do much better then 10 bad scripted. Study databases, maps, cards, etc. You
may not need 100m on equips in a bot, but one with 5~10m in equips will return much more profit then one with NPC equips.
GMs sooner or later will check you, mainly considering you are running more then one bot. If they don't catch you in the first time, they will probably blacklist you, or the map you were then. That's what they do in my servers, btw. If that happens, try to stay low profile for a while, changing the lockmaps, botting time, or don't bot at all.
You can decrease the chances you get caught by studying macros and plugins. Study, study, study. Memorize every config.txt line, and be acquainted with every .txt file in the control folder, save chat_resp, consolecolors, overalauth, responses and sys. Read the manual and start with automacros. The macro plugin forum covers pretty much most GM and players approaches. If any approach you know is missing, try to work on it by yourself. If you need any help on it, come to the forums, but don't expect the others to do the hard work for you, as macros require some tests.
Overstressing, the greedier you are, then most prone you are to a GM check. If you bot 24/7, on telesearch and on the most profitable maps, GMs or players will certainly check you. Try to balance that if you are too worried about getting caught. I'm kinda greedy, but the consequences are familiar to me.
Good luck.