The rules of Texas Hold'em do not care what you are holding the table on. Everything else does: you see less at once, the clock feels shorter, and the device itself starts making decisions for you after an hour. This page is only about that gap.

On a laptop you can see the board, the pot, every stack and the action history without moving your eyes much. On a phone, two or three of those are always off screen or collapsed behind a tap. Nothing has been removed — but information you have to go and fetch is information you will stop fetching once the clock is running.
Most mobile clients let you turn on a warning tone or vibration for the last few seconds. The default is usually off, and the first time you discover this is the first time you get timed out of a hand you wanted to play. Turn it on before the first session, not after.
When the clock is tight, the fastest reliable read is the pot size against what a call costs — one ratio, one number, already on screen. Hand reading takes longer and is the first thing to go wrong under time pressure, so lead with the arithmetic and use the read to adjust it.
The seconds between hands are unmetered and almost everybody wastes them. That is when to check stack sizes, notice who just joined, and decide roughly what you will do with the next few holdings. Decisions made there cost no clock at all.
Three words for things you physically do. All-in puts every chip in and ends your decisions for the hand. Bluff means betting a hand that only wins if the other player folds. Check-raise means passing first and raising after somebody else bets — on a phone it is worth knowing because the two taps come in quick succession.
Three words for things you count. Pot odds is what a call costs against what is already in the middle. Range is the whole set of hands someone could hold at this point rather than one guess. C-bet is a continuation bet — betting the flop after you were the one raising before it. These three carry the most weight on a small screen because they are quick.
Three words for things that happen to you. Tilt is playing worse because of how the last hand went. Value bet is betting to be called rather than to end the hand. Fold equity is the part of your expectation that comes from them giving up. The first is the one mobile play makes more likely, for reasons the next section covers.
After roughly an hour, three things start happening on most phones: the body warms up and the processor slows down to cope, battery saving begins limiting what runs in the background, and the network may quietly hand over between wi-fi and mobile data. Each of them shows up as the same symptom — the table feels sluggish — and none of them is your connection being bad.
The practical answer is to treat session length as a setting rather than a mood. Decide before you start how long you will play, keep the device off a soft surface so it can shed heat, and if you are going past an hour, plug in rather than letting battery saving make the decision for you. A table that lags is a table you will misclick on.

Timer warning on, stack sizes located, session length decided. Three settings, two minutes, and the small screen stops costing you hands.