1.Only invest what you can afford to lose.
2.Never invest in something you dont understand.
You wont immediately understand everything, thats ok. Do some research.
3.Dont day trade unless you spend a minimum of 6 hours a day on the markets.
4. Be patient and buy it on sale.
Your list is enough to start invest activity but some people obey that and trust with other people opinion, that's a mistakes. Actually, invest/ trade basic is same but sometimes market has their own moving price depend the condition, we lost our patience and mostly also lost our money. Know the risk, brave to practice and accept the result is needed. Good luck to all.
Its already been said in the lists, I think that is the best suggestion for the investors to be effective in their investments. The most important thing is you have to have a patience and always do some research before you put any investments.