I usually played laser / rockets tinker anyways, so not much changed for me regarding the tinker nerfs. Maybe the urn cancelling blink dagger nerf hurt my tinker the most. I keep going for the bottle - BoTs - soul ring - blink dagger - dagon and ghost scepter / ethereal somewhere along the way, it still worked for me without any real difference. Granted, I've played only around 3 tinker games since the patch hit.
What really helps is what Ariadne said - try to play 1v1 mid matchups. They might be a bit different from what you encounter on other lanes (mostly different heroes), but it teaches you the basics of controlling lane, harass, last hits, denies and survivability. What I would add is when you go safe lane again try to stick to few heroes at a time, find what works for you. I for example love supporting with CM, Lina or venom (and I hate treant, omni and shadow demon) just because I love to be active on lane and harass the hell out of enemy and/or am also quite effective at early rotations. It also helps to know how aggressive can you be, if you can afford to trade blows with certain hero, how much mana can you count on, how strong your attacks are etc. When laning against solo offlaner try to be aggresive, don't let him earn xp or even worse LH and denies when you are 2v1 on lane and you can force him behind tower. Learn how to control the lane using passive last hits (deny as soon as you can), but not in situations when enemy creeps would get under your tower (that repushes the lane back). Learn when to pull creeps, when your hero needs to tank the enemy creep wave under tower, it's bad and many active players can exploit that. If you are not going to push with double creep wave, first stack and then pull or pull two camps at once. All of these things are small, but they make the difference between average and great lane support.
Other than that, it highly depends on the actual game. Some lanes are really hard to win and you can't do much about that with individual skill.
How can you resolve that is:
- abandon the lane and let one hero alone leech xp and farm woods or rotate. This leaves the laner more vulnerable and won't probably get much farm, you might get something off woods or successfully gank which may in the end offset the loss from the lane.
- change up the lanes. Let that durable offlaner handle it and move your carry to offlane where he may get some farm. Let carry go mid and the mid player with levels safe lane when he already has his basic items and levels. Good luck forcing people to do this on pubs though.
- call for gank. Really, if you are losing lane hard, people from your team should rotate and help, be it ganks from mid player or tp reactions.
- start to 5 man. Easier said than done as well.
More or less in situations where you are losing the lane be it by your mistakes, hero disadvantage or skill difference, you need to play as a team and try to make up for it. What you shouldn't do is return to the lane at all costs when you just get farmed there.