that depends on market conditions and strength of trend. if the trend is strong and in a narrow channel then it makes sense to enter on a first signal. if it is a wider channel then look for signals near the extremes of channel to buy low[in the trend] and sell high [in the trend]. the width of the channel is a trend.
entering before anybody else is not a smart thing to do. if somebody has bought but not bought enough to move the market, that entity will buy more when it has a chance. if you buy after many such entities, they will protect their entry point. so you will have protection of the entire market WHICH YOU NEED unless you are as big as the big 5, who control 80 % of the market ,it is smarter to take their protection, as they will protect their entry, so you have to accept a worse fill, and you are in effect paying the market PROTECTION MONEY for YOUR safety. this is the logic for a second entry. Good fill: bad trade ,bad fill: good trade if you get a better entry price on the second entry than the first entry BEWARE !!!! and look at your market read again since often the market is setting up a trap. so you can pass snide comments that try to show how good you are and how stupid i am but you are thinking wrong and misleading the lesser skilled members of this forum
Al Brooks says the best R/R Entries are on the first Pullback, when the new Trend is barely recognizable.