HI!
Going to add my perspective since India has been my favorite civ for many years but was actually one of the last civs I played much until I discovered how to use them and make them good.
My experience comes from thousands of games of Legacy FFA, but a few years ago took my TR rank to a Major and used mostly India. especially in 1v1. Just as long as your not up against Ports, or China you have a chance. So even with the poorer state India was in then can be made a very effective civ. But I play them a little different.
First The economy, I heavy value a good wood haul to start. India can run low on food or coin and manage ok, but when they are wood poor they come to a screeching halt. I see so many fur trade booms emphasis on so much coin and then they only have so little wood to fight with get in tricky situations. Sure you have 1300 wood to use later but one should not depend on that early on. You may need urumi.
When to trade: well there are 2 ways to go, in a team game a later trade is better but its harder to be as aggressive as India needs to be. A sensible time would be 5 minutes left or send fur trade with 5:40 remaining. a more risky attempt that can leave you food starved and cause a cascading set of problems would be to shoot for 4 minutes. But that also gives little time to coordinate buying units and sending the large consulate armies. After many games had ended I mostly found I had more coin than I ever needed and would be better off not getting wood or food starved. So here is one of the keys that really made India strong and viable to me in TR even with slow train speed. Is not being too greedy with fur trading earlier… with like 6 minutes left before trading a big safety buffer of food is gained. You may have less coin, but you can really delete down villagers since after that will only be collecting food and do not need 100 on food. This gives you a window for a very strong overwhelming army and also helps mitigate the train times where you often have 30-40 pop in training at most times. As long as you are getting the better of the kill ratios and not just letting that extra pop go to waste then its like “doubling” your eco in compared in how effective your opponent can use their resources. Use that extra pop for more high pop units than just spamming out tons of inf.
The objective then is to win the center battle, blitz the center for a FB with sepoy building and then hammer hard to the defenses and break through…
Some things to consider about India differently than other civs. Most civs flood units in to hold a line, and eventually one side breaks to move it forward. India however fights in waves so one might lose an inch of screen to gain 2 then lose one, then gain 2 more. One has to kind of with draw ones troops back to the barracks as new waves comes to reinforce.
Urumi or natives.-- India has some good deck options for TR because it easily maxes out ECO cards and have ample military cards to try different strategies. I used to play with the chakrams and war elephant card. And they certainly are good to consider VS. some match ups. Such as the Brittish where chakrams will really help eat up musket civs. The problem with these is that they eat up a lot of coin and shorten your window to win. I much prefer urumi. and for 750 food that is almost nothing for India and they really add an interesting dynamic to the indian army that really all your waves should be focused around. Building up and retreating until your shipments arrive. Then branching out again. Urumi are great with mahouts since they will create synergy for a melee wall that kills everything and protects them from pike units. This forces the player to make heavy cav which is expensive and India has other great counters for. I like to combine them with extended fortifications so I can make 3-4 towers where I am fighting and pop them out at different flanks.
I tend to rely on sepoy more than howdas, but a few do not hurt… 2-3 is enough just to use as sniping units for cav that get too close to the front lines or sensitive things. I never much liked using India like a skirm goon civ and I think those that do are the ones that find it weaker.
I also do not make many gurkas. 5-10-15 is enough. Just to pressure them at range. The problem is a sweeping heavy cav push can ruin a whole army and that can be very difficult to come back from. So lots of sepoy sometimes get sacrificed to protect the key components that allow them to surgically rip apart armies and bases. If they do send in a cav charge use Sepoy in melee.
There are always times and civs that break the rules. Aztec can make lots of gurkas, Vs Lakota, make howdas and mahouts, etc…) And if what you are doing is not working try switching it up, or splitting the battle to a second place. Never be fixed… its like port players who get fixed on making jinetes when no one is making cav… don’t do that!
Camels-- units I never made but may be viable now that train times are faster but still I think camels in TR do not belong as are just too weak and take up too many card spots to make worth while. If one can spam them out in a low pop situation that could be useful but costly. Remember to make 20 tigers at all time its often the difference between a holding battle and winning steam roll.
No real need to make Rajputs. Upgrading flail elephants is optional but not recommended. They can be a cheap way to take out large FB’s quickly but with walls the AI will stupidly attack segments that don’t matter. But also can be a low pop way to cause some pings on your enemy screen for attention and soften up walls to make a jump to later. or just make them think you are to send troops there.
I know there is a lot of conjecture on siege eles but really they are great. The speed is not to be taken lightly but they should tie culverins in range… or have a resist from siege which I think is actually a better way to make them not TOO op at killing falconetes yet not dying to culvs so easily and essentially cancel each other out per pop and cost. India may never have a good answer for port and Japans long range mortars. but they are death to India as you cant stop them and cant protect your FB.
Mahouts… are… awesome… and… risky. well they will kill infantry faster than cannons can but you gotta kinda watch after them and micro them like you would a cannon to targets. Running from bad engagements, and getting through the ranks to attack the right units… this is where the urumi waves really help clear the path. And all that area melee damage is just so magnificent to see working right.
Start Consulate armies. Everyone expects french gendarmes and they are good and I think DE nerfed it for that matter. But what I always liked better was the 5 falconet or any cannon shipment really. When India is not supposed to have cannons and then does and you have this big start army it can be quite strong.
Other great cards besides the standard ones are the one that adds the castle build limit, extra 10 tigers,
If you are using a ranged mansabar put them in stand still stance and they will live longer.
When to use Taj… it can be tempting to try to use it to breach a wall and get in a eco. For inexperienced players this can work and be GG or even a rage quit. but for a pro you will likely get blocked or consumed and lose your army and momentum. So I mostly use it to either save my base from a side flank, or more regularly if I get in a tough spot and need an army again. For that it can really save you… with bases be patient, and blast a big big holes to get through before committing to over extending to try to snipe the TC.
Its a challenging civ and strong and well rewarding for those that use it right. Have fun GL!