There is no way to guarantee you're approved for a loan, but there are some key steps you can take before you apply:
Work out how much you can borrow. Lenders have criteria to decide how much you're eligible to borrow, but you also need to understand what is realistically affordable for you.
Maintain a good credit score or improve it. A lower credit score can reduce your chances of getting approved or mean you are offered a higher interest rate. If you already have a poor credit score, you can start improving it by limiting credit applications, paying bills on time and bringing down any limits on your credit card. It can take a while, but these are all good tactics to improve that credit score.
Keep track of your saving goals. If you manage to contribute to your savings regularly, it shows lenders that you are likely to manage ongoing loan repayments.