First of all once you choose a broker, always try its Demo environment. And for me it is very important that it should be the same as the live one (excepting the slippage). In addition, it is preferable if the Broker have the option to test the ESMA conditions on demo.
Here is the list of my criteria on which I choose to review and test a Broker.
- Inter-core bank spreads – not fixed as with the Market makers
- NDD/ STP/DMA Broker
- Data and funds security
- Negative Balance protection and needed risk policies - this is applicable for all EU brokers (due to ESMA regulations from 01.08.2018)
- No bonuses and markups
- Trading platforms
- Good customer service
- Commission based broker
- Free Add-ons package (it is working on demo as well)
- 1 type of account for all its clients
- 100% anonymity (our LPs never see your stops, limits and entry orders)
- Member of ICF (Investor Compensation Fund) as I am European resident
In conclusion, you could also review Broker Discussion section. There is a lot of detailed information.