The Psalms in the Old Testament are full of matters brought to God in prayer, apart from praise. Yes, those Psalms were set to music and sung by God's covenant people in worship, and they teach us a great deal about prayer. Thanksgiving is a core theme, so keep doing that, but read the following and learn what else you can pray about:
Psalm 4; 5; 6; 9; 10; 11; 12; 14; 15; 16; 19; 20; 22; and by then you should be hooked on reading the Psalms as inspiration for your prayers. Notice how many of them start with praise and thanksgiving? That is the way to start prayers, but there is so much more to pray about!
However, if you are a believer who is somewhat isolated from the world-wide Church, you might need to educate yourself on what's going on around the world, with your brothers and sisters in Christ. That is a massive area for prayer. Also, if you are keen to share the good news about Jesus to others, you need to be in touch with those who do that, to learn from them matters of prayer to progress that vital ministry. There are, for example, various Bible Societies translating the scriptures into languages of very small groups of people, and getting the Bible to them. They covet our prayers. Expand your contacts with other Christians and you will soon find no end of matters to take to God in prayer, for prayer is the power-house of the Church (which is why so many church groups are spiritually weak - they are not devoted to prayer, as fellowships.) Learn to pray for the needs of others.