Very nice and even quite "history-like" is to actually use your skirmishers as a screen in front of your main line. Deploy them in LOOSE formation, skirmish-mode OFF, gard-mode ON, 4-6 men deep just in front of your line, where usually everybody also have a few javelins. ut fire-at will of those line troops ON as well. It is especially great when you are defending, but works fine in offence too.
The beauty of this line up is, that the enemy will waste its javelins (which would otherwise cause a lot damage to your usually not-so-much-armored line troops) on the relatively cheap skirmishers who being in loose formation usually do not suffer too high casualties. On the other hand, the skirmishers pepper the enemy with their missiles and once engaged in melee delay him still while your line troops hurl their javelins in turn. Thus the enemy is severely weakened and his morale lowered by successive volleys of javelins even before the "real" battle fully begins. Once your main line dispatch all of their javelins, order the skirmishers to retreat back to safety and your fresh line infantry to charge the enemy. Usually the rsult is a short melee followed by a mass rout of demoralized enemy with very low losses on your side.
Simple, quasi-historical (no need for noobish slinger armies or too much cavalry), works-like a charm!