There are 4 stages to any stock. Knowing these and being able to identify them with ease is the first step to becoming a successful investor
1. Accumulation
The first stage to any bullish run. A long period of sideways movement between levels of support and resistance. Identifying this gives investor a clear entry point. When the security is near its support - perfect time to start accumulating
2. Markup
The second stage - the security is starting to move upwards in price. This is also called a breakout. Often during this stage traders use the likes of moving averages to make decisions on when to buy and sell. This stage is where profits are made
3. Distribution
Assets price is starting to flatten out. Bearish investors start to put more pressure on bulls. Some indicators start losing their strength - this can be a sign of upcoming down move
4. Markdown
The stage when assets loses its value. This often is much more aggressive and happens faster than stage 2. Stop orders placed at stage 3 should help you reduce the losses while the asset is losing its value
Based on the above - S&P500 is currently in stage 1 where assets should be accumulated at the right price near the support levels.
You want to be prepared for the next bull run