1. The learning curve will be steep and in the process, you WILL lose money with some careless mistakes that you are likely to make for starters.
2. There are lots of hidden cost involved in running a gold farm. These hidden costs can varies exponentially depending on the size of your farm but for starters, you should always have back-up cash to tide you through if you are facing 3 straight months of negative revenue.
These hidden costs includes, time and money for new account training
VPS/servers upkeep, investment in scripts for various platforms and methods, botting platform monthly fees and risk assessment done to include the chances of getting wiped.
3. I will not recommend sticking to strictly one botting platform to perform your farm. Some platforms tend to be targeted more so than the others so this diversification strategy will help you tide over a platform-based targeted ban.
It will be wise to have multiple in-game scripts for methods for Simba (Pascal/colour), Tribot (Java/Reflection & Colour), OSbot (Java & Groovy/injection). These three coincidentally also happens to be popular botting platforms.
Good luck on your gold farming journey!