As Terran you have a lot of tools that allow you to see if your opponent is preparing for a cheese or all-in type of attack. At the Bronze level, this is one of the most difficult things to learn to start doing. These tools include scans, Banshees, flying buildings, stimmed Marines, and Hellions. Once you know what your opponent is going for (such as by scanning their base, seeing 2 Stargates, and expecting Void Rays), you can start trying to exploit their strategy. In the Void Ray example, you can use the Void Ray's slight lack of mobility and weakness to Marines against them by performing drops with Medivacs.
One common tactic that almost all pro Terran players use is to scan first before attacking. This gives you a much better sense of what your opponent is doing, and if you see a massive Void Ray fleet, you can make the active decision not to move out with your army.
Another important thing to note is that early pressure is often very important. Allowing your opponent to sit back completely undisturbed will often cost you the game. It is usually best to at least put on a little bit of pressure in the early game. For example, against Protoss, you can attack with 2 Marines and a Marauder right after you finish Concussive Shells. This attack, while obviously not meant to completely end the game, will pressure your opponent into building more units, expending Force Field energy, and delaying their expansion.
Overall, if you don't want the game to simply result in a base trade, don't wait until both your armies are maxed out to attack. Think about it from the other player's perspective. If you see a maxed 200/200 army attacking you, and you know that your own units are out of position to deal with it, you only really have 2 options. The first, is to wait until you can get a better position and reposition your units. This will often lead to substantial losses to your front lines (which may include a new expansion or production facilities). The second, is to simply counter attack. When you're in this situation, you often have to weigh the two choices, and if it turns out that you think you have a higher chance winning by a counter attack (base trade), then that is the option you will likely pick.
- Attack early with your units. Don't wait until you have tier 3 units (Thors) before attacking. Even a small group of 8 Marines and 1 Medivac is enough to really harass your opponent.
- Gain map awareness with your units. Do this by controlling Watchtowers, Scanning, or using Air units.
Doing this allows you to gain small, incremental victories over your opponent, which, in the long run, will allow you to win the game. However, keep in mind that whenever an opponent is really far behind, they will likely result in all-in tactics.