If price spends too much time at support / resistance, it is more likely that the support / resistance zone is very strong and price is very weak to break this zone. In other words, a support / resistance zone breakout is usually valid & convincing.....
b) Strong Volume, usually higher than the previous candle volumes; in case of Index, volume is not available; hence this can be used in futures / stocks. Usually in a liquid instrument a strong candle is caused by strong volume, which is not the case with illiquid stock...