1. Mention to Engage
You can optimise engagement on Twitter by @mentioning people, brands, etc. inside of tweet. Tweetdeck is a recommended tool for finding twitter handles easily due to the auto-complete and comprehensive search result feature.
2. Queue ‘Em Up!
You can easily create queue slots on HootSuite and Buffer and just queue up tweets ahead of time to deal with issues like lack of WiFi/internet access, low battery, etc. With the Buffer app you can have up to 10 slots on the free version and unlimited on the paid version, while HootSuite suggest when best to schedule your tweet based on when your followers are most active.