There are several approaches that may work. I'm not sure which methods are most easily available for a user of a blockchain.info-wallet, but probably #0a and #2, followed by #3, #0b and #1b.
0) Wait it out.
0a) Wait for the transaction to go through. Most likely there will be free capacity in the network after some hours, some days or a week. In periods with free capacity, even low-fee transactions will pass. Rarely one has to wait longer than the next Sunday evening.
0b) Wait for the transaction to be forgotten, and then create a new transaction with a higher fee. In some few exceptional cases (notably around new year 2017/2018) several weeks or even months have passed without any free capacity. The original transaction may eventually be forgotten by the network. Some wallets will then offer to create a new transaction, Mycelium will offer to delete the old transaction, and with some luck a "double spend" will be possible - though this is very unreliable as the original transaction may be purposely or accidentally rebroadcast both by the sender, receiver and any third-party.
0c) While you're anyway waiting for it to go through you may try to actively rebroadcast the transaction (not sure if the blockchain.info-wallet supports it - it may be done through external software though). This probably won't help at all, and it's the exact opposite of 0b, so it's probably not a good idea (from some wallets this may be the most intuitive panic action, therefore I think it still ought to be mentioned).
1) Double spend with a higher fee (RBF).
1a) Using the "Replace by Fee"-protocol - this probably does not apply to you, but I'll still leave it here as it arguably is the best way to "unstick" transactions. If the original transaction was marked up with "RBF allowed", most of the network will accept the new transaction and discard the old one. Not all wallets supports setting this flag, I don't believe the Blockchain-wallet supports it - and even if the Blockchain-wallet supports it, it's even less likely the RBF-flag was turned on by default. RBF can be used for reverting an unconfirmed transaction (though very few wallets supports creating such an "undo-transaction") - so using the RBF-flag is a terrible idea if you want something done by a zero-conf, say, buying a coffee - you may end up not getting the coffee until it's cold. (the RBF-feature has been removed from most Bitcoin Cash software, as they deem it both "harmful" and "not needed").
1b) Doing RBF/"Double spend" even if the original transaction was not marked as RBF. Miners (and nodes) are supposed to ignore the double spend transaction - but you may be lucky. You may need to use some other wallet or even specialized software to perform such a double spend. It may work, either because the original transaction has ended up in a "ghost-like" state where it's known by some nodes but not others - maybe some miners are unaware that you're doing a double-spend - or it may work because some miners deliberately accepts double-spent transactions as they can earn more fees on it.
2) Child Pays for Parent (CPFP). if a new transaction is made with a high fee, building on top of the old transaction, most of the miners will include the whole chain of transaction in the block they're mining at. A normal transaction has two "outputs" (aka "UTXO"s), one going to the receiver of the funds, the other going back to the same wallet. Making a new transaction with any of those two UTXOs will help. One notable exception, if all funds in the wallet was sent, there won't be any change-UTXO, and 2b below will not apply.
2a) Get the receiver of the funds to spend the funds they received on a new transaction, with high fee. This may of course not always be possible, but ...
2b) Spend the "change UTXO". Some wallets has a menu option for "accelerating" the transaction through "CPFP". If that's not supported, you can always send all the funds in the wallet (the funds can be sent back to an address belonging to the same wallet). One problem with this is that the fees may become very high (particularly if you've been using your wallet for a while and never emptied it completely - then it's most likely filled up with "dust" making such a transaction big and costly). Some wallets let you hand-craft the transaction so you may send just the "change UTXO" back to youself. In worst case you may move the private key or the wallet seed to some other wallet. Electrum does support spending some specific UTXO, and Mycelium has the "CPFP" acceleration button.
3) Ask the pools for help. viabtc has their "transaction accelerator" at https://pool.viabtc.com/tools/txaccelerator/, antpool.com also has some similar service, there even exists services where one can pay by credit card to get the transaction prioritized.