frenzyxMake sure if you win mid you have one scout chase the medic, and one scout cap. If you only have 1 scout have him cap, and your team move up.
Though for the most part this is true, it triggers me when team A wins mid and has 4 up vs the 3 up of team B, but instead of continuing to chase and potentially wipe them, one of the scouts jerks off on middle capping while his team attempts to win the team fight without him. There's nothing wrong with killing them and then capping afterwards, especially given scout is the best class in the game it is pretty useful to chase meds even if it means you have to cap later (or have your roamer switch to pain train and cap it as he respawns).
On the topic of playing pocket on middle, don't think you always need to jump in and initiate something for your team. Especially on maps like gullywash, it's often straight up suicidal to attend. Otherwise to jump into the enemy team because there are usually 6 players grouped up on one side ready to kill whoever feeds into them. That being said, standing on the low ground and spamming/attracting spam to your team can also sometimes be detrimental (for example if your roamer is bombing or something like that). You can bait your roamer a little bit by having him bomb in and you jump in slightly afterwards and shoot the dudes shooting your teammate or who he's shooting. I think there's a few old vods on boinks youtube of technosex talking about double bombs on mid if you're unfamiliar with the concept.
In pugs and stuff when I play pocket, I sometimes find that it's more effective to go gunboats and do a roamer style jump and attempt to make a distraction so your team can push across point and shoot the dudes looking at you. On most mods at least, neither soldier should be taking too many heals (besides arrows and initial buffs) so the role of pocket and roamer tend to blur a little, though at a lower level it may be better for you to try to babysit your medic if you don't 100 percent trust your scouts to hit all their shots/avoid tunnel visioning.