There are plenty of online resources to help you practise your Welsh. Why not give the Duolingo app a go or listen to Say Something In Welsh? The Cymorth Cymraeg website may also be helpful. Originally set up for staff at Bangor University, it's a useful resource for anyone using Welsh at work.
Helping with grammar
If you've got a smartphone, the English-Welsh dictionary app, ‘Ap Geiriaduron’, is very useful.
Other useful resources include the Cysill and Cysgair spelling and grammar checks for your computer. Online dictionaries are also handy, try geiriadur.net, Geiriadur yr Academi or the University of Wales's dictionary.
Term Cymru is a valuable online resource if you use Welsh at work.