At the highest level of competition in Drop Assault, a barrier to getting more points is that bases don't refresh on your map as fast as you can destroy them. When you reach the point where your map is clear of enemy bases, you need to wait until the enemy takes some bases back before you can get more glory. Understanding the rate that bases "refresh" (i.e. become available for attack again) on your map is important if you want to compete at this level.
First, if you have a larger map, you will have more potential targets. So your refresh rate will be higher. This is why it's important to level up your base quickly, and get the maximum level on your logistics building as soon as possible.
Second, bases on your map will refresh faster if you have more of your map cleared. For example, if you completely clear your map, you can expect 6 or so bases to refresh in the next hour. If your map has 20 available targets, new ones will only refresh about every 30 minutes. If your map is half-full, it could take 2-3 hours for another base to refresh.
So to increase the potential number of points you can get, keep your map clear of targets as often as possible. For example, if you clear your map once per day, you will get significantly less glory than if you clear it twice per day. This is because you will get the faster refresh rates for more time of the day.
For this reason, it's valuable to attack NPC bases even if you can't get the bonus objective. It may seem worthless since the 5 glory you gain will be lost when the base is taken back, but removing it from your map will speed up the refresh rate of your map. For example, if you leave a half-dozen of these bases on your map, you will never get the 6/hour refresh rate of an empty map. You will only get 3/hour at best.
Tip: You gain glory when you destroy a base, but lose 5 of that glory when it refreshes. But, for the purpose of tournaments (either person tournaments which are weekly or chapter tournaments which are monthly), if you are already at zero, that loss of 5 glory does not count since you can't go negative. So one trick is to let a few bases refresh on your map at the beginning of a tournament, since those refreshes can't hurt you. Then you can quickly take many bases and get the full benefit from those bases without the -5 glory you would normally incur.
If you are in a position in a tournament where losing some glory will not affect the outcome, consider letting bases on your map refresh at the end of the tournament as well, to have more available targets at the start of the next tournament.
During these periods where you don't mind losing glory and want bases to refresh, some players even make their base very easy to defeat (e.g. by stowing all their turrets). The lost glory from the attack on their base won't affect the tournament, but once the next tournament starts, they will have a bunch of revenge opportunities to get more glory. If you are using this tactic, beware that you may lose most/all your heroes. So be prepared to revive some when you are ready to attack (and remember to re-deploy your turrets...)