Stream vods of my pocket soldier "tutorial" ahould be up at http://www.twitch.tv/yookstah . Check the latest videos. My gfx card decides to crash halfway through so thats a bummer.
Will edit post with points that more or less echo thoughts in my vid
EDIT: OKAY, here we go. Apologies if I echo other people's posts/thoughts - I just want to get as much stuff out as I can before I forget it.
There are two very important things that you have to remember when talking about ubers. There are some other things, obviously, but these are two of the most important that I can think of. The first thing: Make sure you don't try and do too much with the uber. You'll notice in just about any game that the pocket on either side of the team will try and do too much with the uber, or will seem frustrated he didn't get some instant frags and will jump off and die, leaving his medic stranded, then the uber fight and post uber fight is screwed. Have a general plan for the uber and don't try and kill everything. Obviously, things can change on the fly, so try and dictate the uber to the best of your ability to your team "We've ubered around choke, they're multi'ing alot, I've done a lot of damage, their ubers out, come around choke now, they're retreating grey bridge". Dictating the fight is probably the most important thing, especially in uber because it's such a short time and so much can happen in that 8 or less seconds (depending on flashes, mind you). Remember it is okay to just take positioning with the uber and play spread out to make sure that, if they still have uber then you can escape with minimal losses - and have hopefully forced their uber in a poopy position for them.
The second thing to remember is, expanding on my previous point, the uber isn't everything. If you'll notice in a few of our games, I didn't always do A LOT with the uber. A good portion of the time, I would just simply force the opposing teams uber, call to my team that's all I'm doing and for them to play passive (maybe sheep kills 10 people on the flank in the process if lucky), and play for the post uber. If I have forced flashes and their team to waste uber; if no one else on my team has taken (much) damage, then our post uber is stronger than theirs - we have a demo with 8 stickies loaded coming around with 150% hp, scout coming in as well, roamer and scout (presumably) pressuring the flank, and I'm spamming from somewhere I cannot really be attacked. Expanding on this, you don't always have to have wait for uber. Have confidence in your team and their abilities and punish teams for being complacent thinking you are just going to wait for uber. This can be hard to do on some maps, especially depending on the utilities the other team is running (mostly on last points), but you still have room to do some aggressive stuff to catch the other team off guard. Assuming you don't lose too many people, if you at least trade, you have the previous control point to back up to. Nothing ventured, nothing gained.
Something to keep in mind during ubers is that you don't really want to tunnel the combo players. One of the things I do the most in a lot of ubers is just helping out my team on the flank/elsewhere. A soldier on 300 hp with pretty much full ammo and an uber tick landing into a 1v1 heavily skews the fight in your favour (who would have thought?) It's not necessarily about getting picks; it's more about keeping your teammates alive for the post uber/next fight. This is especially easy to do on viaduct as pocket; the distance between 'the fight' and the flank is only a rocketjump away (generally), so there is a lot of opportunity to help the rest of your team in fights. Remember it is not all about how 'good' your uber is (i.e. forcing multi ubers is cool and all), it's all about how your team is at the end of the uber, making sure you have enough people alive/in fighting shape for the post uber fight, which is where the real magic happens.
Another point I can mention is health and ammo before/during/after ubers. I feel that this is one of my strongest points as pocket and why a lot of my ubers are generally effective, or that my post ubers are strong, too. A lot of the time, I call an early uber pop if I just want to get in there and get stuff done. [timestamp from vod pending] a good example is this where in our game against HRG on snakewater, I believe we have even players and ubers, their combo is towards saw and they have a scout and some other players near the point. I call for an early uber from the right side ramp in lobby, jump the point, kill the scout and get another pick (?). Doing this I have blocked the point, got some picks, and have lost no players in the midst of it, and have full health after and during the uber. If there is some reason where someone needs a flash in the middle of the uber, it is much safer to do when your team has ubered early as, if you're on 300HP you have that buffer - if you try and milk the uber too much and your med lets you drop low on hp, they need to use most of the uber keeping you alive and healing you, allowing you to do less during the uber and being more tethered to your medic, and keeping your team alert to not require a flash.
Going on the ammo point, you don't really want to waste too much ammo during an uber. As I keep harping on about, the post uber tends to be the more important fight, so make sure you have enough ammo in reserve/loaded ready to go for that fight. On the note of ammo during uber: don't be afraid to reload rockets in the midst of it. Obviously you generally want to have your full ammo loaded BEFORE you uber, but if you use a decent amount during the uber don't be afraid to reload a rocket or two to juggle the other team instead of flailing around with your shotgun. Manipulation of movement of the other team can be more important than just going for that TLR shotgun frag. Make your rockets count in the uber (read: try not to miss, unless it's chasing airshots!!), and go for the easy yet effective shots where possible.
I also have a question on what to do if another of our players get caught in a solo uber and forces us to flash especially like a demo who can't get out as easily.
A demoman can actually very easily get out of the fight in a lot of cases if he has an uber flash; he can sticky jump away. However, failing this presence of mind by the demoman, your life a lot of the time is forfeit moreso than theirs. This is due to the obvious reason of the defensive power of the demoman, giving you stickies to fall back on if the fight turns out poorly for you and falling back to the second point if need be. This is especially true on a map like badlands where it is stupidly easy to spam the spire if you have fallen back from attacking last.
I also feel I get greedy with ubers a lot of the time because watching over demos of our scrims, I almost always take the initial uber in, sometimes giving it to our scouts if we have a good advantage. In what cases would a demo uber be more beneficial to a push?
It is okay to take most of the ubers as pocket, because it is very easy for you to do the initial part of the uber, paving way for the rest of your team, and having them full health/ammo for the post uber fight. In post uber fights you are typically on a spam angle being a pest, or landing in their face while your demo and scout(s) come in behind you as you have paved the way for them with your initial uber. Taking other classes like scouts and demo is good depending on what you want to do. A good example would be attacking badlands last with uber advantage: you can push top left with demo/scout, other team is either forced onto floor/into resup, demo stickies top left + point, scout baits point, win game.