Level 235 requires quite a lot of attention on your part. First of all, try to quickly make some room to create bombs as detonating bombs is the only way to get rid of the earth tiles. The trick is to destroy at least one of the crates as soon as possible as this will fill up the empty area with pieces and increase the chances of making good matches. The higher the destroyed crate is, the easier it will be to win this level.
Also, please note that it is not necessary to destroy the upper left and the bottom right crates. It is quite hard to reach them, and there are no golden tiles behind them.
In addition, you really need to keep a close eye on the field, as it is essential that you do not lose any chances to make power-ups. Do not rush into using them though – try to get a couple of power-ups close to each other and activate them in a single move. This will clear more space and will charge the Lightning power-up faster.